Computational thinking is mainly used for:

Solving problems in a logical way

According to the book, computational thinking is:

Not only for computer science students

Only for computer science students

In computational thinking, which of these do we do with unnecessary details?

Remove them and focus on important points

What is the LAST step shown in Figure 2.1: Computational Thinking in Daily Life?

Algorithm Design: Create Step-by-Step Solution

Decomposition: Break Down the Problem

Pattern Recognition: Find Patterns

Abstraction: Focus on What's Important

Which of these is a benefit of decomposition given in the book?

It allows us to focus on one task at a time

It works only in computer science

Why must the steps of a solution be in the correct order?

To prevent errors during problem solving

Logic helps computers:

Store, understand, and use information correctly

In computer science, logic means:

Using rules to make correct decisions

According to the book, logic is used in:

Expert systems and artificial intelligence

A proposition is a statement that is:

Both true and false at the same time

A proposition is usually represented by:

A capital letter, such as P, Q, or R

A compound proposition is formed by:

Combining two or more simple propositions

Breaking a simple proposition into smaller parts

Only the first statement is true

Reverse the truth of a statement

Turn a proposition into a question

Class 12 · Chapter 2

Chapter 2 MCQs with answers: Computational Thinking & Algorithms

157 MCQs from 12 sections, each with the correct answer.

115 short and long questions of this chapter

2.1 Introduction to Computational Thinking

1.
Computational thinking is mainly used for:
1. a)Playing computer games
2. b)Solving problems in a logical way Correct answer
3. c)Writing essays
4. d)Drawing pictures
Explanation
Book Answer Key (page 32): B. From the book: "Computational thinking is a way of thinking to solve problems clearly and logically. It helps us break big problems into smaller and simpler parts."
2.
According to the book, computational thinking is:
1. a)Only for computer science students
2. b)Not only for computer science students Correct answer
3. c)Only for engineers
4. d)Only for computers
Explanation
From the book: "This thinking is not only for computer science students."
3.
According to the TIDBIT, computational thinking is used by scientists, engineers, and even ______ when planning complex tasks.
1. a)chefs Correct answer
2. b)drivers
3. c)farmers
4. d)painters
Explanation
TIDBIT (page 20): "Computational thinking is used by scientists, engineers, and even chefs when planning complex tasks."
4.
Computational thinking means thinking like a:
1. a)Computer
2. b)Scientist
3. c)Problem solver Correct answer
4. d)Poet
Explanation
From the book: "Computational thinking means thinking like a problem solver. It focuses on understanding a problem step by step."
5.
In computational thinking, the clear steps we create to solve a problem can be followed by:
1. a)Computers only
2. b)Humans only
3. c)Humans or computers Correct answer
4. d)Neither humans nor computers
Explanation
From the book: "We then create clear steps to solve the problem. These steps can be followed by humans or computers."
6.
In computational thinking, which of these do we do with unnecessary details?
1. a)Add more of them
2. b)Remove them and focus on important points Correct answer
3. c)Write them down first
4. d)Repeat them in every step
Explanation
From the book: "We remove unnecessary details and focus on important points."
7.
According to the book, sorting books by subject or size shows:
1. a)Decomposition
2. b)Pattern recognition Correct answer
3. c)Decision making
4. d)Thinking ahead
Explanation
From the book (Real-life examples of Computational Thinking): "Sorting books by subject or size shows pattern recognition."
8.
According to the book, which activity includes breaking tasks into smaller parts?
1. a)Planning a trip Correct answer
2. b)Fixing a mobile phone problem
3. c)Sorting books
4. d)Playing strategy games
Explanation
From the book: "Planning a trip includes breaking tasks into smaller parts." Fixing a mobile phone problem "uses logical thinking", sorting books "shows pattern recognition" and playing strategy games "requires thinking ahead".
9.
According to the book, cooking a recipe uses:
1. a)Pattern recognition
2. b)Step-by-step instructions Correct answer
3. c)Thinking ahead
4. d)Decision making
Explanation
From the book: "Cooking a recipe uses step-by-step instructions."
10.
According to the book, managing money needs:
1. a)Planning and decision making Correct answer
2. b)Pattern recognition only
3. c)Thinking ahead only
4. d)Step-by-step instructions only
Explanation
From the book: "Managing money needs planning and decision making."
Watch the lessons
Every topic explained step by step. A new video every week.
Subscribe on YouTube(opens in a new tab)
11.
In Figure 2.1: Computational Thinking in Daily Life, which step is labelled "Focus on What's Important"?
1. a)Decomposition
2. b)Pattern Recognition
3. c)Abstraction Correct answer
4. d)Algorithm Design
Explanation
Figure 2.1 (page 21) labels its four steps "1. Decomposition, Break Down the Problem", "2. Pattern Recognition, Find Patterns", "3. Abstraction, Focus on What's Important" and "4. Algorithm Design, Create Step-by-Step Solution".
12.
What is the LAST step shown in Figure 2.1: Computational Thinking in Daily Life?
1. a)Decomposition: Break Down the Problem
2. b)Pattern Recognition: Find Patterns
3. c)Abstraction: Focus on What's Important
4. d)Algorithm Design: Create Step-by-Step Solution Correct answer
Explanation
Figure 2.1 (page 21) numbers its steps 1 to 4, and step "4. Algorithm Design" is labelled "Create Step-by-Step Solution". It matches the text: "We then create clear steps to solve the problem."

2.2 Problem Solving Using Computational Thinking

13.
The first step in problem solving is:
1. a)Writing code
2. b)Evaluating the solution
3. c)Identifying the problem Correct answer
4. d)Breaking the problem
Explanation
Book Answer Key (page 32): C. From the book (Identifying a Problem Clearly, page 21): "Identifying a problem clearly is the first and most important step in problem solving."
14.
Breaking a large problem into smaller parts is called:
1. a)Abstraction
2. b)Decomposition Correct answer
3. c)Evaluation
4. d)Automation
Explanation
Book Answer Key (page 32): B. From the book (page 21): "Breaking a problem into smaller parts is called decomposition."
15.
A step-by-step solution to a problem is known as an:
1. a)Program
2. b)Flowchart
3. c)Algorithm Correct answer
4. d)Function
Explanation
Book Answer Key (page 32): C. From the book (Creating Step-by-Step Solutions, page 21): "Creating step-by-step solutions helps us solve problems in an organized way. These steps are known as algorithms."
16.
Problem solving using computational thinking helps us solve problems in a:
1. a)Fast but careless way
2. b)Logical and organized way Correct answer
3. c)Random way
4. d)Difficult way
Explanation
From the book: "Problem solving using computational thinking helps us solve problems in a logical and organized way."
17.
Problem solving using computational thinking helps reduce:
1. a)Mistakes and confusion Correct answer
2. b)Time and money
3. c)Steps and rules
4. d)Questions and answers
Explanation
From the book: "It helps reduce mistakes and confusion. Computational thinking improves overall problem-solving ability."
18.
According to the DO YOU KNOW? box, computers solve problems in the way humans do when they use computational thinking, but:
1. a)Much slower
2. b)With more mistakes
3. c)Much faster Correct answer
4. d)Without any steps
Explanation
DO YOU KNOW? (page 21): "Computers solve problems in the way humans do when they use computational thinking, but much faster!"
19.
When identifying a problem, it is important to know the given information and the:
1. a)Expected result Correct answer
2. b)Programming language
3. c)Number of steps
4. d)Unnecessary details
Explanation
From the book (Identifying a Problem Clearly): "It is important to know the given information and the expected result."
20.
While identifying a problem clearly, unnecessary details should be:
1. a)Written first
2. b)Ignored Correct answer
3. c)Repeated
4. d)Added to the solution
Explanation
From the book (Identifying a Problem Clearly): "Asking simple questions helps in understanding the problem better. Unnecessary details should be ignored. A clear problem leads to a correct solution."
Watch the lessons
Every topic explained step by step. A new video every week.
Subscribe on YouTube(opens in a new tab)
21.
Which of these is a benefit of decomposition given in the book?
1. a)It makes the problem bigger
2. b)It allows us to focus on one task at a time Correct answer
3. c)It removes the need for steps
4. d)It works only in computer science
Explanation
From the book (Breaking a Problem into Smaller Parts (Decomposition)): "Decomposition helps us organize our thoughts. It allows us to focus on one task at a time. This method is widely used in computer science and daily activities." So option d is wrong: it is used in daily activities too.
22.
Why must the steps of a solution be in the correct order?
1. a)To make the solution longer
2. b)To prevent errors during problem solving Correct answer
3. c)To hide the steps from others
4. d)To make the problem bigger
Explanation
From the book (Creating Step-by-Step Solutions): "The steps must be in the correct order. This prevents errors during problem solving."
23.
In Figure 2.2: Step by Step Algorithm Example, which step comes right after "Boil Water"?
1. a)Serve Tea
2. b)Add Milk or Lemon
3. c)Steep Tea Correct answer
4. d)End
Explanation
Figure 2.2 (page 22) shows the steps in this order: Start, Boil Water, Steep Tea, Add Milk or Lemon, Serve Tea, End.
24.
According to the book, evaluation helps us check:
1. a)If the solution is correct Correct answer
2. b)How long the problem is
3. c)Who made the solution
4. d)The number of smaller parts
Explanation
From the book (Evaluating and Improving Solutions): "After finding a solution, it is important to evaluate it. Evaluation helps us check if the solution is correct. It allows us to find and fix mistakes."
25.
What shows whether a solution works properly?
1. a)Decomposition
2. b)Testing the solution Correct answer
3. c)Ignoring details
4. d)Asking simple questions
Explanation
From the book: "Testing the solution shows whether it works properly."
26.
According to the book, we can improve a solution by making it:
1. a)Longer or harder
2. b)Simpler or faster Correct answer
3. c)Bigger or slower
4. d)Secret or hidden
Explanation
From the book: "We can improve the solution by making it simpler or faster. This process helps us learn from errors. Improving solutions leads to better performance."
27.
Arrange the four parts of problem solving in the order the book teaches them: (1) Evaluating and Improving Solutions, (2) Identifying a Problem Clearly, (3) Creating Step-by-Step Solutions, (4) Breaking a Problem into Smaller Parts (Decomposition).
1. a)1, 2, 3, 4
2. b)2, 4, 3, 1 Correct answer
3. c)4, 2, 1, 3
4. d)2, 3, 4, 1
Explanation
The book's sub-headings in 2.2 come in this order: Identifying a Problem Clearly ("the first and most important step in problem solving"), Breaking a Problem into Smaller Parts (Decomposition), Creating Step-by-Step Solutions, and Evaluating and Improving Solutions ("After finding a solution, it is important to evaluate it.").

2.3 Logic as a Knowledge Representation Framework

28.
According to the book, logic is:
1. a)The science of true reasoning Correct answer
2. b)A type of computer hardware
3. c)A way to store pictures
4. d)A programming language
Explanation
From the book: "Logic is the science of true reasoning and is an important concept in computer science."
29.
Logic helps computers:
1. a)Run without electricity
2. b)Store, understand, and use information correctly Correct answer
3. c)Print documents faster
4. d)Connect to the internet
Explanation
From the book: "It helps computers store, understand, and use information correctly."
30.
Using logic, complex information can be represented:
1. a)Only as pictures
2. b)In a longer way
3. c)In a simple way Correct answer
4. d)Only on paper
Explanation
From the book: "Using logic, complex information can be represented in a simple way."
31.
In computer science, logic means:
1. a)Using rules to make correct decisions Correct answer
2. b)Using random guesses
3. c)Drawing diagrams
4. d)Storing data in tables
Explanation
From the book: "In computer science, logic means using rules to make correct decisions."
32.
Logic helps computers understand:
1. a)Colours and sounds
2. b)Human feelings
3. c)Only large numbers
4. d)True and false conditions Correct answer
Explanation
From the book: "Logic helps computers understand true and false conditions."
33.
Logical statements are used in programs and algorithms. What do these statements help to do?
1. a)Increase screen brightness
2. b)Control the flow of programs Correct answer
3. c)Cool down the processor
4. d)Delete old files
Explanation
From the book: "Logical statements are used in programs and algorithms. These statements help control the flow of programs."
34.
According to the book, logic helps computers think in a:
1. a)Random way
2. b)Emotional way
3. c)Structured way Correct answer
4. d)Slow way
Explanation
From the book: "Logic is the basis of many computer operations. It helps computers think in a structured way."
35.
Using logic, decisions are made based on:
1. a)Facts and rules Correct answer
2. b)Luck
3. c)Guesswork
4. d)Feelings
Explanation
From the book: "Using logic, decisions are made based on facts and rules. It removes confusion and guesswork."
36.
What does logic remove from reasoning and decision making?
1. a)Facts and rules
2. b)Confusion and guesswork Correct answer
3. c)Steps and conclusions
4. d)Computers and humans
Explanation
From the book: "Using logic, decisions are made based on facts and rules. It removes confusion and guesswork."
37.
Logic ensures that decisions are:
1. a)Fast but wrong
2. b)Different every time
3. c)Consistent and accurate Correct answer
4. d)Based on guesses
Explanation
From the book: "Logic ensures that decisions are consistent and accurate."
38.
According to the book, logic is used in:
1. a)Expert systems and artificial intelligence Correct answer
2. b)Only pocket calculators
3. c)Only video games
4. d)Only printers
Explanation
From the book: "It is used in expert systems and artificial intelligence."
39.
The TIDBIT says logic gives computers a way to "think" about facts and make decisions, almost like:
1. a)A calculator
2. b)A brain Correct answer
3. c)A camera
4. d)A library
Explanation
From the book's TIDBIT: "Logic gives computers a way to "think" about facts and make decisions, almost like a brain."

2.4 Propositional Logic

40.
The logic that uses only true or false values is:
1. a)Predicate logic
2. b)Fuzzy logic
3. c)Propositional logic Correct answer
4. d)Natural logic
Explanation
Book answer key: "C". From the book: "Propositional logic is a basic form of logic used in computer science. It deals with statements that can be true or false."
41.
A compound proposition is:
1. a)(P)
2. b)(Q)
3. c)(P∧Q) Correct answer
4. d)True
Explanation
Book answer key: "C". From the book: "A compound proposition is formed by combining two or more simple propositions. Logical connectives are used to join them." (P) and (Q) are single propositions, and True is a truth value. Note: topic 2.4 writes the connective as the word AND and never shows the symbol ∧. In logic, ∧ means AND, so (P∧Q) means "P AND Q": two simple propositions joined by a connective.
42.
A proposition is a statement that is:
1. a)Both true and false at the same time
2. b)Either true or false Correct answer
3. c)Neither true nor false
4. d)Always true
Explanation
From the book: "A proposition is a statement that is either true or false. It cannot be both true and false at the same time."
43.
Which of the following is NOT a proposition?
1. a)"The sun rises in the east"
2. b)"2 + 3=5"
3. c)"Close the door." Correct answer
4. d)"1 > 3"
Explanation
From the book: "Questions and commands are not propositions." "Close the door." is a command. The book gives "The sun rises in the east" as a proposition, and Figure 2.3 shows "2 + 3=5" (True) and "1 > 3" (False) as propositions.
44.
A proposition is usually represented by:
1. a)A number, such as 1, 2, or 3
2. b)A capital letter, such as P, Q, or R Correct answer
3. c)A symbol, such as + or -
4. d)A full sentence in brackets
Explanation
From the book: "A proposition is usually represented by a capital letter, such as P, Q, or R."
45.
According to the book, propositions are:
1. a)The basic units of logic Correct answer
2. b)Questions with no answer
3. c)Commands given to a computer
4. d)Names of programs
Explanation
From the book: "Propositions are the basic units of logic. They are used to form logical expressions."
46.
"It is raining" is an example of a:
1. a)Compound proposition
2. b)Logical connective
3. c)Command
4. d)Simple proposition Correct answer
Explanation
From the book: "A simple proposition contains only one statement. It cannot be broken into smaller parts. For example, "It is raining" is a simple proposition."
47.
"It is raining and it is cold" is a:
1. a)Simple proposition
2. b)Compound proposition Correct answer
3. c)Question
4. d)Truth table
Explanation
From the book: "For example, "It is raining and it is cold" is a compound proposition." Two simple propositions are joined by the connective "and".
48.
A compound proposition is formed by:
1. a)Breaking a simple proposition into smaller parts
2. b)Asking two questions
3. c)Combining two or more simple propositions Correct answer
4. d)Writing a capital letter
Explanation
From the book: "A compound proposition is formed by combining two or more simple propositions. Logical connectives are used to join them."
49.
Which logical connective is used when both statements must be true?
1. a)AND Correct answer
2. b)OR
3. c)NOT
4. d)IF
Explanation
From the book: "AND is used when both statements must be true." Figure 2.4: "True if both A and B are true."
50.
OR is used when:
1. a)Both statements must be false
2. b)At least one statement is true Correct answer
3. c)No statement is true
4. d)Only the first statement is true
Explanation
From the book: "OR is used when at least one statement is true." Figure 2.4: "True if A or B is true (or both)."
51.
NOT is used to:
1. a)Join two propositions
2. b)Reverse the truth of a statement Correct answer
3. c)Make a statement longer
4. d)Turn a proposition into a question
Explanation
From the book: "NOT is used to reverse the truth of a statement." Figure 2.4: "Not A" is "True if A is false."
52.
According to Figure 2.4, "A or B" is true:
1. a)Only if both A and B are true
2. b)Only if A is false
3. c)If A or B is true (or both) Correct answer
4. d)Never
Explanation
Figure 2.4: Logical Connectives, OR row: "True if A or B is true (or both)."
53.
In Figure 2.3, the statement "1 > 3" is shown as:
1. a)True
2. b)False Correct answer
3. c)Both true and false
4. d)Not a proposition
Explanation
Figure 2.3: Propositional Logic Statements shows "1 > 3" with an arrow to "False" (1 is not greater than 3). It is still a proposition, because "A proposition is a statement that is either true or false."
54.
According to the DO YOU KNOW? box, propositional logic is the simplest type of logic, but it:
1. a)Is never used in computers
2. b)Forms the base of all computer reasoning Correct answer
3. c)Works only with numbers
4. d)Can be both true and false
Explanation
From the book's DO YOU KNOW? box: "Propositional logic is the simplest type of logic, but it forms the base of all computer reasoning!"

2.5 Truth Tables

55.
The purpose of a truth table is to:
1. a)Write programs
2. b)Store data
3. c)Evaluate logical expressions Correct answer
4. d)Design algorithms
Explanation
Book answer key: "C". From the book: "The main purpose of truth tables is to show how a logical expression behaves. They help us find when a statement is true or false." Truth tables "help in checking the correctness of logical expressions."
56.
A truth table lists:
1. a)Only the true cases
2. b)All possible combinations of truth values Correct answer
3. c)Only the first row of values
4. d)The names of all programs
Explanation
From the book: "A truth table lists all possible combinations of truth values. It shows the final result for each combination."
57.
The main purpose of truth tables is to:
1. a)Show how a logical expression behaves Correct answer
2. b)Make a program run faster
3. c)Store propositions in memory
4. d)Replace logical connectives
Explanation
From the book: "The main purpose of truth tables is to show how a logical expression behaves."
58.
For n propositions, a truth table has:
1. a)n rows
2. b)2n rows
3. c)2ⁿ rows Correct answer
4. d)n² rows
Explanation
From the book: "Truth tables enumerate all possible combinations (2ⁿ rows for n propositions)."
59.
How many rows does the truth table for two propositions A and B have?
1. a)2
2. b)3
3. c)4 Correct answer
4. d)8
Explanation
The book's rule is "2ⁿ rows for n propositions". For n = 2: 2 × 2 = 4 rows. Figure 2.5 (A and B) has exactly 4 rows.
60.
How many rows does a truth table need for three propositions P, Q and R?
1. a)3
2. b)6
3. c)8 Correct answer
4. d)9
Explanation
The book's rule is "2ⁿ rows for n propositions". For n = 3: 2 × 2 × 2 = 8 rows (checked by listing every True/False combination of three values).
61.
In Figure 2.5, when A is True and B is False, A AND B is:
1. a)True
2. b)False Correct answer
3. c)Both True and False
4. d)Not defined
Explanation
Figure 2.5: Truth Table for Logical Expressions, row 2: A = True, B = False, A AND B = False. "AND is used when both statements must be true" (topic 2.4), and here B is false.
62.
In Figure 2.5, A OR B is False only when:
1. a)A is True and B is True
2. b)A is True and B is False
3. c)A is False and B is True
4. d)A is False and B is False Correct answer
Explanation
Figure 2.5, last row: A = False, B = False, A OR B = False. In the other three rows at least one of A and B is True, so A OR B is True.
63.
In Figure 2.5, NOT A is True when:
1. a)A is True
2. b)A is False Correct answer
3. c)B is True
4. d)A and B are both True
Explanation
Figure 2.5: the NOT A column is True in the two rows where A is False, and False where A is True.
64.
Creating a truth table starts with:
1. a)Writing the final result
2. b)Identifying the propositions Correct answer
3. c)Drawing a flowchart
4. d)Applying NOT to every value
Explanation
From the book: "Creating a truth table starts with identifying the propositions."
65.
While creating a truth table, logical connectives are applied:
1. a)Step by step Correct answer
2. b)Only in the first row
3. c)Before the propositions are identified
4. d)Never
Explanation
From the book: "All possible combinations of truth values are listed. Logical connectives are applied step by step. The final result is written for each row."
66.
Each proposition P or Q can take the value:
1. a)1, 2 or 3
2. b)Yes, No or Maybe
3. c)True (T) or False (F) Correct answer
4. d)Only True (T)
Explanation
From the book: "Each proposition P or Q can take the value True (T) or False (F)."
67.
The truth value of a compound proposition is determined by:
1. a)The length of the sentence
2. b)The values of its components Correct answer
3. c)The first letter of the proposition
4. d)The number of rows only
Explanation
From the book: "Truth value of a compound proposition is determined by the values of its components."
68.
Which of these is NOT a use of truth tables given in the book?
1. a)Checking the correctness of logical expressions
2. b)Comparing different logical statements
3. c)Removing confusion in logical reasoning
4. d)Storing data on a hard disk Correct answer
Explanation
From the book: truth tables "help in checking the correctness of logical expressions", "They help compare different logical statements", and "They help remove confusion in logical reasoning." The book never says they store data.

2.6 Propositional Equivalence

69.
Propositional equivalence explains when two logical expressions:
1. a)Have the same meaning Correct answer
2. b)Use the same symbols
3. c)Have the same number of propositions
4. d)Are always false
Explanation
From the book: "Propositional equivalence is a concept in propositional logic. It explains when two logical expressions have the same meaning."
70.
Propositional equivalence is checked using:
1. a)Flowcharts
2. b)Truth tables Correct answer
3. c)Venn diagrams only
4. d)Algorithms
Explanation
From the book: "Propositional equivalence is checked using truth tables."
71.
Two expressions are equivalent if they have the same truth values:
1. a)In the first row only
2. b)In at least one case
3. c)In all cases Correct answer
4. d)In most cases
Explanation
From the book: "If two expressions have the same truth values in all cases, they are equivalent."
72.
Which symbol is used to show equivalence?
1. a)∧
2. b)∀
3. c)≡ Correct answer
4. d)∃
Explanation
From the book: "The symbol "≡" is used to show equivalence."
73.
Even if two expressions look different, they may:
1. a)Give the same result Correct answer
2. b)Never be compared
3. c)Always be false
4. d)Need different truth tables to be equal
Explanation
From the book: "Even if expressions look different, they may give the same result."
74.
Besides truth tables, what else can help identify equivalence?
1. a)Logical laws Correct answer
2. b)Variables only
3. c)Quantifiers
4. d)Flowcharts
Explanation
From the book: "Logical laws can also help identify equivalence. These laws simplify expressions."
75.
When equivalent logical expressions are identified, each expression is tested for:
1. a)One chosen truth value
2. b)All possible truth values Correct answer
3. c)Only true values
4. d)Only false values
Explanation
From the book: "Equivalent logical expressions are identified using truth tables. Each expression is tested for all possible truth values. If the results match in every case, they are equivalent."
76.
Equivalence allows us to replace complex expressions with:
1. a)Longer ones
2. b)Simpler ones Correct answer
3. c)Unsatisfiable ones
4. d)Random ones
Explanation
From the book: "Equivalence is important because it helps simplify logic problems. It allows us to replace complex expressions with simpler ones. This saves time and effort."
77.
In programming, equivalent expressions improve:
1. a)Screen brightness
2. b)Code efficiency Correct answer
3. c)Typing speed
4. d)Internet speed
Explanation
From the book: "In programming, equivalent expressions improve code efficiency. Equivalence helps avoid logical errors."
78.
According to Figure 2.6, (A AND NOT B) OR (B AND NOT A) is logically equivalent to:
1. a)(A AND B) OR (NOT A AND NOT B)
2. b)(A OR B) AND (NOT A OR NOT B) Correct answer
3. c)A AND B
4. d)NOT A OR NOT B
Explanation
From Figure 2.6 of the book: "Therefore: (A AND NOT B) OR (B AND NOT A)⟺(A OR B) AND (NOT A OR NOT B)". Its truth table gives F, T, T, F for both expressions (rows FF, FT, TF, TT). Option c is true only in row TT and option d is true in rows FF, FT and TF, so they do not match. Option a gives T, F, F, T, the exact opposite.
79.
Figure 2.6 says both expressions are true in the same cases. Which name does the figure give these cases?
1. a)AND
2. b)NOT
3. c)XOR Correct answer
4. d)NAND
Explanation
From Figure 2.6 of the book: "Both expressions are true in the same cases (XOR)."
80.
In the truth table of Figure 2.6, what is the value of (A AND NOT B) OR (B AND NOT A) when A = T and B = T?
1. a)T
2. b)F Correct answer
3. c)Both T and F
4. d)It cannot be found
Explanation
From Figure 2.6 of the book: the row "T T" gives "F" in both expression columns. A AND NOT B is F (NOT B is F), and B AND NOT A is F (NOT A is F), so F OR F is F.
81.
According to the TIDBIT, equivalent expressions may look different but:
1. a)Always give the same result Correct answer
2. b)Always give different results
3. c)Never simplify logic
4. d)Are always unsatisfiable
Explanation
From the book's TIDBIT: "Equivalent expressions may look different but always give the same result; they help simplify complex logic."

2.7 Propositional Satisfiability

82.
A proposition that is true for at least one case is called:
1. a)Unsatisfiable
2. b)Invalid
3. c)Satisfiable Correct answer
4. d)Equivalent
Explanation
Book answer key: "8. C" (Satisfiable). From the book: "A proposition is satisfiable if there is at least one combination of truth values that makes it true." DO YOU KNOW?: "A logical expression is satisfiable if there is at least one way to make it true."
83.
Propositional satisfiability is a concept in logic that checks whether a statement:
1. a)Can be true Correct answer
2. b)Is always false
3. c)Has two variables
4. d)Is written in English
Explanation
From the book: "Propositional satisfiability is a concept in logic that checks whether a statement can be true. It helps us know if a logical expression has at least one situation where it is true."
84.
If all possible combinations of truth values make a proposition false, it is:
1. a)Satisfiable
2. b)Unsatisfiable Correct answer
3. c)Equivalent
4. d)A predicate
Explanation
From the book: "If all possible combinations make it false, it is unsatisfiable."
85.
Satisfiability depends on:
1. a)The length of the expression only
2. b)The structure of the expression and the logical connectives used Correct answer
3. c)The number of people who read it
4. d)The font of the expression
Explanation
From the book: "Satisfiability depends on the structure of the expression and the logical connectives used. Logical connectives like AND, OR, and NOT determine whether a statement can be true."
86.
According to the book, one way to test satisfiability is:
1. a)Checking all possible cases using a truth table Correct answer
2. b)Checking only the first case
3. c)Counting the letters in the expression
4. d)Drawing a flowchart
Explanation
From the book: "Checking all possible cases using a truth table is one way to test satisfiability."
87.
Which of these is the book's example of an unsatisfiable expression?
1. a)P OR Q
2. b)P AND Q
3. c)P AND NOT P Correct answer
4. d)NOT P
Explanation
From the book: "An unsatisfiable expression is "P AND NOT P." This is never true because P cannot be both true and false." P OR Q and P AND Q are the book's satisfiable examples.
88.
The expression "P AND Q" is true when:
1. a)Only P is true
2. b)Only Q is true
3. c)Both P and Q are true Correct answer
4. d)Both P and Q are false
Explanation
From the book: "Another example is "P AND Q," which is true when both P and Q are true."
89.
Why is "P AND NOT P" never true?
1. a)Because P is always true
2. b)Because P cannot be both true and false Correct answer
3. c)Because NOT has no meaning
4. d)Because it has two variables
Explanation
From the book: "This is never true because P cannot be both true and false."
90.
The book's example "Bring pizza OR (burger AND do NOT bring soda)." is:
1. a)Unsatisfiable, no solution exists
2. b)Satisfiable, a solution exists Correct answer
3. c)Neither satisfiable nor unsatisfiable
4. d)True in every case
Explanation
From the book: "Result: Bring pizza, no soda = satisfiable expression. Solution exists." Checked by listing all 8 cases: the expression is true in 5 of them, so it is not true in every case (option d is wrong).
91.
The statement "You must bring pizza AND you must NOT bring pizza." is:
1. a)Satisfiable
2. b)Unsatisfiable Correct answer
3. c)Equivalent to "Bring pizza"
4. d)True when pizza is brought
Explanation
From the book: "Result: No solution exists = unsatisfiable expression."
92.
According to the book, satisfiability is important for:
1. a)Designing algorithms and verifying programs Correct answer
2. b)Printing documents
3. c)Storing pictures
4. d)Charging batteries
Explanation
From the book: "Satisfiability helps us test logical statements and make decisions. It is important for designing algorithms and verifying programs."
93.
How many true outcomes does an unsatisfiable expression have?
1. a)At least one
2. b)Exactly one
3. c)None Correct answer
4. d)All of them
Explanation
From the book: "Satisfiable expressions have at least one true outcome, while unsatisfiable expressions have none."
94.
In the expression "P OR Q", which choice of values makes it FALSE?
1. a)P true, Q false
2. b)P false, Q true
3. c)P true, Q true
4. d)P false, Q false Correct answer
Explanation
From the book: "P OR Q" "is true if either P or Q is true." So it is false only when neither is true: P false and Q false. (It is also true when both are true, because OR "is used when at least one statement is true", topic 2.4.) It is satisfiable because it has true outcomes.

2.8 Predicate Logic

95.
Predicate logic is mainly used to:
1. a)Draw diagrams
2. b)Represent relationships using variables Correct answer
3. c)Store numbers
4. d)Design networks
Explanation
Book answer key: "10. B" (Represent relationships using variables). From the book: "In predicate logic, we can talk about individuals, groups, and relationships between them" and "Predicate logic, on the other hand, uses predicates and variables to express detailed statements."
96.
Predicate logic is an extension of:
1. a)Fuzzy logic
2. b)Propositional logic Correct answer
3. c)Natural logic
4. d)Computer networks
Explanation
From the book: "Predicate logic is an extension of propositional logic. It allows us to express more detailed statements about objects and their properties."
97.
A predicate is a statement that can be true or false depending on:
1. a)The values of the variables Correct answer
2. b)The size of the page
3. c)The number of connectives
4. d)The truth table heading
Explanation
From the book: "A predicate is a statement that can be true or false depending on the values of the variables."
98.
Why is "x is greater than 5" a predicate?
1. a)Because it is always true
2. b)Because it depends on x Correct answer
3. c)Because it has no variable
4. d)Because it is always false
Explanation
From the book: "For example, "x is greater than 5" is a predicate because it depends on x."
99.
Predicate logic studies statements that contain:
1. a)Only numbers
2. b)Variables and predicates Correct answer
3. c)Only true values
4. d)Pictures and tables
Explanation
From the book: "Predicate logic studies statements that contain variables and predicates."
100.
The predicate "isEven(x)" is true if:
1. a)x is an odd number
2. b)x is greater than 5
3. c)x is an even number Correct answer
4. d)x is zero only
Explanation
From the book: "For example, "isEven(x)" is true if x is an even number."
101.
Variables represent objects or values in the:
1. a)Truth table
2. b)Domain of discourse Correct answer
3. c)Computer memory
4. d)Logical connective
Explanation
From the book: "Variables represent objects or values in the domain of discourse."
102.
Which statement about propositional logic is correct according to the book?
1. a)It is more expressive than predicate logic
2. b)It can describe relationships between objects
3. c)It is easier to understand but less flexible Correct answer
4. d)It uses predicates and variables
Explanation
From the book: "Propositional logic is easier to understand but less flexible." It "cannot describe properties of objects or relationships between them", and "Predicate logic is more expressive and powerful than propositional logic."
103.
Propositional logic cannot describe:
1. a)Simple statements
2. b)Statements that are true or false
3. c)Properties of objects or relationships between them Correct answer
4. d)Logical connectives
Explanation
From the book: "Propositional logic deals with simple statements that are either true or false. It cannot describe properties of objects or relationships between them."
104.
In the predicate logic expression Tall(Ali), the word "Tall" is the:
1. a)Subject
2. b)Property Correct answer
3. c)Variable
4. d)Connective
Explanation
From the book: "Tall(Ali)", "Can see subject Ali + property Tall". Ali is the subject and Tall is the property.
105.
In the book's comparison, which point is listed under Propositional Logic for A = "Ali is Tall"?
1. a)Cannot see inside (A) Correct answer
2. b)Always false
3. c)Uses two variables
4. d)Is a predicate
Explanation
From the book: Propositional Logic, A = "Ali is Tall", with the two points "Cannot see inside (A)" and "Limited". In predicate logic, Tall(Ali) "Can see subject Ali + property Tall" and is "Much more expressive".
106.
In Figure 2.7 "Predicate Logic Structure", x and y are shown as:
1. a)Predicates
2. b)Variables Correct answer
3. c)Truth values
4. d)Quantifiers
Explanation
From Figure 2.7 of the book: the box "Predicate" holds "Helps", and two arrows go to two boxes headed "Variable", holding x and y. The label below reads "Helps (x, y)".
107.
According to the book, predicate logic is used to represent knowledge:
1. a)Randomly
2. b)Formally Correct answer
3. c)In pictures only
4. d)Without variables
Explanation
From the book: "Predicate logic allows expressing statements like "All students are hardworking" or "Some books are interesting." It is used to represent knowledge formally."

2.9 Quantifiers in Predicate Logic

108.
The symbol for the universal quantifier is:
1. a)∃
2. b)⟶
3. c)∧
4. d)∀ Correct answer
Explanation
Book answer key: "9. D" (∀). From the book: "The universal quantifier is used to indicate that a statement is true for all objects in a given set (as shown in Figure 2.8). It is denoted by the symbol "∀"."
109.
Quantifiers are used in predicate logic to describe:
1. a)The colour of objects
2. b)How many objects satisfy a condition Correct answer
3. c)The speed of a program
4. d)The size of a table
Explanation
From the book: "Quantifiers are used in predicate logic to describe how many objects satisfy a condition."
110.
According to the book, quantifiers make predicate logic more powerful than:
1. a)Propositional logic Correct answer
2. b)Algorithms
3. c)Truth tables
4. d)Flowcharts
Explanation
From the book: "Quantifiers make predicate logic more powerful than propositional logic."
111.
The existential quantifier is denoted by the symbol:
1. a)∀
2. b)∃ Correct answer
3. c)→
4. d)∧
Explanation
From the book: "The existential quantifier is used to indicate that a statement is true for at least one object in a set (as shown in Figure 2.8). It is denoted by the symbol "∃"."
112.
The universal quantifier indicates that a statement is true for:
1. a)Exactly one object in a set
2. b)No object in a set
3. c)All objects in a given set Correct answer
4. d)At least one object in a set
Explanation
From the book: "The universal quantifier is used to indicate that a statement is true for all objects in a given set". Option d describes the existential quantifier.
113.
What does "∀x, x > 0" mean?
1. a)There exists at least one x that is greater than 0
2. b)For all x, x is greater than 0 Correct answer
3. c)For all x, x is less than 0
4. d)No x is greater than 0
Explanation
From the book: "For example, "∀x, x > 0" means "For all x, x is greater than 0.""
114.
What does "∃x, x is even" mean?
1. a)Every x is even
2. b)No x is even
3. c)There exists at least one x that is even Correct answer
4. d)x is always odd
Explanation
From the book: "For example, "∃x, x is even" means "There exists at least one x that is even.""
115.
The existential quantifier is used when a condition is satisfied by:
1. a)Every object in the domain
2. b)Some object but not necessarily all Correct answer
3. c)No object at all
4. d)Only numbers greater than 0
Explanation
From the book: "This quantifier is used when a condition is satisfied by some object but not necessarily all."
116.
Using "for all" ensures that:
1. a)At least one object breaks the statement
2. b)No object in the set violates the statement Correct answer
3. c)The set has only one object
4. d)The statement is about one specific object
Explanation
From the book: "Using "for all" ensures that no object in the set violates the statement."
117.
"∃x, P(x)" means:
1. a)P(x) is true for all x
2. b)P(x) is false for all x
3. c)P(x) is true for at least one x Correct answer
4. d)P(x) is a proposition with no variable
Explanation
From the book: ""∀x, P(x)" means the predicate P(x) is true for all x, while "∃x, P(x)" means P(x) is true for at least one x."
118.
In Figure 2.8 (Universal and Existential Quantifier), the box below "∃x" reads:
1. a)For all x, P(x)
2. b)For some x, P(x) Correct answer
3. c)For no x, P(x)
4. d)Helps (x, y)
Explanation
Figure 2.8 shows "∀x" leading to "For all x, P(x)" under "Universal Quantifier", and "∃x" leading to "For some x, P(x)" under "Existential Quantifier".
119.
What does "∀x ∃y, x < y" mean?
1. a)There is one y that is smaller than every x
2. b)For every x there exists a y that is greater than x Correct answer
3. c)Every x is equal to y
4. d)There exists an x that is greater than every y
Explanation
From the book: "Quantifiers can also be used together in complex statements. For instance, "∀x ∃y, x < y" means for every x there exists a y that is greater than x."
120.
Which statement does the book give as an example of what quantifiers let us write?
1. a)"All students are hardworking" Correct answer
2. b)"2 + 2 = 4"
3. c)"Close the door"
4. d)"Is it raining?"
Explanation
From the book: "Using quantifiers, we can write statements like "All students are hardworking" or "Some books are interesting.""
121.
According to the book, the existential quantifier is important for:
1. a)Storing data
2. b)Drawing pictures
3. c)Problem solving and reasoning Correct answer
4. d)Designing networks
Explanation
From the book: "It helps in expressing possibilities and specific examples. The existential quantifier is important for problem solving and reasoning." (The universal quantifier, by contrast, "is important in mathematics and logic proofs.")

2.10 Applying Predicate Logic to Real-World Problems

122.
According to the book, predicate logic can be used to solve real-world problems by:
1. a)Drawing pictures of the problem
2. b)Representing knowledge clearly and systematically Correct answer
3. c)Storing numbers in a table
4. d)Writing longer programs
Explanation
From the book: "Predicate logic can be used to solve real-world problems by representing knowledge clearly and systematically."
123.
Predicate logic helps us model situations involving:
1. a)Objects, their properties, and relationships Correct answer
2. b)Only numbers
3. c)Only true or false sentences with no objects
4. d)Colours and shapes
Explanation
From the book: "It helps us model situations involving objects, their properties, and relationships."
124.
According to the DO YOU KNOW? box, predicate logic can model:
1. a)Only bank accounts
2. b)Family trees, social networks, and even computer programs Correct answer
3. c)Only weather reports
4. d)Only school timetables
Explanation
DO YOU KNOW? box: "Predicate logic can model family trees, social networks, and even computer programs!"
125.
In the book's example, Borrows(x, y) means:
1. a)"book x borrows student y"
2. b)"teacher x teaches student y"
3. c)"student x borrows book y" Correct answer
4. d)"student x returns book y"
Explanation
From the book: "For example, Borrows(x, y) means "student x borrows book y,""
126.
In the book's example, Teaches(t, s) means:
1. a)"teacher t teaches student s" Correct answer
2. b)"student t teaches teacher s"
3. c)"student t borrows book s"
4. d)"teacher t borrows book s"
Explanation
From the book: "and Teaches(t, s) means "teacher t teaches student s." These predicates clearly describe how students, books, and teachers are connected."
127.
Using relationships such as Borrows(x, y) and Teaches(t, s), the book says we can model the working of:
1. a)A hospital
2. b)A bank
3. c)The library system Correct answer
4. d)A traffic signal
Explanation
From the book: "Using such relationships, we can model the working of the library system. This makes it easier to organize and understand interactions between different entities."
128.
What does "∀x, Student(x) → Borrows(x, Book)" mean, according to the book?
1. a)"some student borrows a book"
2. b)"every student borrows a book" Correct answer
3. c)"no student borrows a book"
4. d)"every book borrows a student"
Explanation
From the book: "For example, ∀x, Student(x) → Borrows(x, Book) means "every student borrows a book."" The symbol ∀ means "for all". Note: in the printed formula "Book" is used like the name of one object; a fully formal way to write "every student borrows a book" is ∀x (Student(x) → ∃y (Book(y) ∧ Borrows(x, y))). The answer follows the book's stated meaning.
129.
What does "∃y, Book(y) ∧ Available(y)" mean, according to the book?
1. a)"every book is available"
2. b)"no book is available"
3. c)"there exists at least one book that is available" Correct answer
4. d)"every student borrows a book"
Explanation
From the book: "∃y, Book(y) ∧ Available(y) means "there exists at least one book that is available.""
130.
According to the book, quantifiers allow us to describe both:
1. a)Colours and sizes of books
2. b)General situations and specific cases in the library system Correct answer
3. c)Hardware and software
4. d)Input and output devices
Explanation
From the book: "These statements help define rules and conditions in a precise way. Quantifiers allow us to describe both general situations and specific cases in the library system."
131.
If "∀x, Student(x) → HasLibraryCard(x)" and "Ali is a student," then we conclude:
1. a)"Ali is a librarian."
2. b)"Ali has a library card." Correct answer
3. c)"Every library card belongs to Ali."
4. d)"Ali borrows every book."
Explanation
From the book: "For example, if "∀x, Student(x) → HasLibraryCard(x)" and "Ali is a student," then we conclude "Ali has a library card.""
132.
The book says this logical reasoning helps in decision making, such as:
1. a)Choosing the colour of a library card
2. b)Checking whether a student can borrow a book Correct answer
3. c)Counting the pages of a book
4. d)Printing a book
Explanation
From the book: "This logical reasoning helps in decision making, such as checking whether a student can borrow a book."
133.
The CLASS ACTIVITY asks students to write rules like "All students must attend class" using:
1. a)Existential quantifiers
2. b)Truth tables
3. c)Universal quantifiers Correct answer
4. d)Flowcharts
Explanation
CLASS ACTIVITY: "Ask students to write rules like "All students must attend class" using universal quantifiers." The word "All" points to "for all", the universal quantifier ∀.
134.
According to the book, reasoning with predicate logic in the library system:
1. a)Ensures correct and consistent conclusions, making the system reliable and easy to manage Correct answer
2. b)Makes the system slower and harder to manage
3. c)Removes the need for any rules
4. d)Works only for numbers
Explanation
From the book: "It ensures correct and consistent conclusions, making the system reliable and easy to manage."

2.11 Logic-Based Reasoning and Inference

135.
Logic-based reasoning and inference are ways of thinking that help us:
1. a)Draw conclusions from known facts Correct answer
2. b)Draw pictures from data
3. c)Store facts in memory
4. d)Guess answers without facts
Explanation
From the book: "Logic-based reasoning and inference are ways of thinking that help us draw conclusions from known facts."
136.
Logic-based reasoning uses rules of logic to reach conclusions:
1. a)Randomly
2. b)Step by step Correct answer
3. c)Without any facts
4. d)Only by guessing
Explanation
From the book: "This method uses rules of logic to reach conclusions step by step."
137.
Logical inference is the process of:
1. a)Deleting old facts
2. b)Deriving new facts from known information Correct answer
3. c)Drawing a flowchart
4. d)Writing a program in Python
Explanation
From the book: "Logical inference is the process of deriving new facts from known information. It is a way of reasoning that follows logical rules."
138.
If we know "All humans are mortal" and "Socrates is a human," we can infer that:
1. a)"All mortals are humans."
2. b)"Socrates is not mortal."
3. c)"Socrates is mortal." Correct answer
4. d)"Socrates is the only human."
Explanation
From the book: "For example, if we know "All humans are mortal" and "Socrates is a human," we can infer that "Socrates is mortal.""
139.
According to the book, logical inference ensures that conclusions are true if:
1. a)The premises are true Correct answer
2. b)The premises are false
3. c)The conclusion is long
4. d)Most people agree
Explanation
From the book: "Logical inference ensures conclusions are true if the premises are true."
140.
According to the book, logical inference is used in:
1. a)Mathematics, computer science, and artificial intelligence Correct answer
2. b)Cooking only
3. c)Painting and music only
4. d)Sports only
Explanation
From the book: "It is used in mathematics, computer science, and artificial intelligence."
141.
Inference helps in making decisions based on:
1. a)Luck
2. b)Evidence Correct answer
3. c)Opinions only
4. d)Colours
Explanation
From the book: "Inference helps in making decisions based on evidence."
142.
Deduction is a type of reasoning that starts from:
1. a)A specific conclusion to reach general facts
2. b)General facts to reach a specific conclusion Correct answer
3. c)Random guesses to reach a rule
4. d)Pictures to reach numbers
Explanation
From the book: "Deduction is a type of reasoning that starts from general facts to reach a specific conclusion."
143.
Which logical rules are used in deduction, according to the book?
1. a)"if-then" statements Correct answer
2. b)Loops
3. c)Colour codes
4. d)Tables of contents
Explanation
From the book: "Logical rules like "if-then" statements are used in deduction."
144.
"If it rains, the ground gets wet" and "It is raining" lead to the conclusion:
1. a)"It will stop raining."
2. b)"The ground is dry."
3. c)"The ground is wet." Correct answer
4. d)"It rains every day."
Explanation
From the book: "For example, "If it rains, the ground gets wet" and "It is raining" lead to the conclusion "The ground is wet.""
145.
Why is deduction reliable?
1. a)Because it uses many examples
2. b)Because the conclusion is guaranteed to be true if the premises are true Correct answer
3. c)Because computers never make mistakes
4. d)Because it starts from a specific conclusion
Explanation
From the book: "Deduction is reliable because the conclusion is guaranteed to be true if the premises are true."
146.
Using the book's "if-then" rule pattern: "If a student has a library card, the student can borrow a book" and "Sara has a library card". Which conclusion follows by deduction?
1. a)"Sara cannot borrow a book."
2. b)"Every student has a library card."
3. c)"Sara can borrow a book." Correct answer
4. d)"Sara is a librarian."
Explanation
This follows the book's own pattern: ""If it rains, the ground gets wet" and "It is raining" lead to the conclusion "The ground is wet."" In the same way, the "if-then" rule plus the fact that its "if" part is true gives the "then" part. "Deduction is a type of reasoning that starts from general facts to reach a specific conclusion."
147.
According to the book, computers use deduction to:
1. a)Charge their batteries
2. b)Solve problems and answer questions Correct answer
3. c)Print documents faster
4. d)Connect to the internet
Explanation
From the book: "Computers use deduction to solve problems and answer questions. Deduction helps in formal reasoning and problem-solving tasks."

Exercise from the book

148.
Computational thinking is mainly used for:
Book exercise
1. a)Playing computer games
2. b)Solving problems in a logical way Correct answer
3. c)Writing essays
4. d)Drawing pictures
Explanation
From book page 32 Answer Key: B. Topic 2.1 Introduction to Computational Thinking (page 20): "Computational thinking is a way of thinking to solve problems clearly and logically. It helps us break big problems into smaller and simpler parts." Summary (page 30): "Computational thinking is a problem-solving approach in which a problem is understood, broken into smaller parts, and solved step by step using logical thinking."
149.
The first step in problem solving is:
Book exercise
1. a)Writing code
2. b)Evaluating the solution
3. c)Identifying the problem Correct answer
4. d)Breaking the problem
Explanation
From book page 32 Answer Key: C. Topic 2.2, Identifying a Problem Clearly (page 21): "Identifying a problem clearly is the first and most important step in problem solving. We must understand what the problem is asking." Breaking the problem (decomposition) and creating step-by-step solutions come next, and evaluating comes last: "After finding a solution, it is important to evaluate it." (page 22).
150.
Breaking a large problem into smaller parts is called:
Book exercise
1. a)Abstraction
2. b)Decomposition Correct answer
3. c)Evaluation
4. d)Automation
Explanation
From book page 32 Answer Key: B. Topic 2.2, Breaking a Problem into Smaller Parts (Decomposition) (page 21): "Breaking a problem into smaller parts is called decomposition." Summary (page 30): "Decomposition is the process of breaking a large or complex problem into smaller and manageable parts." Abstraction is a different step: Figure 2.1 (page 21) labels it "Focus on What's Important". Evaluation is checking a solution: "Evaluation helps us check if the solution is correct." (page 22).
151.
A step-by-step solution to a problem is known as an:
Book exercise
1. a)Program
2. b)Flowchart
3. c)Algorithm Correct answer
4. d)Function
Explanation
From book page 32 Answer Key: C. Topic 2.2, Creating Step-by-Step Solutions (page 21): "Creating step-by-step solutions helps us solve problems in an organized way. These steps are known as algorithms." Summary (page 30): "An algorithm is a step-by-step set of instructions used to solve a problem or perform a task." Figure 2.2: Step by Step Algorithm Example (page 22) shows making tea in order: Start, Boil Water, Steep Tea, Add Milk or Lemon, Serve Tea, End.
152.
The logic that uses only true or false values is:
Book exercise
1. a)Predicate logic
2. b)Fuzzy logic
3. c)Propositional logic Correct answer
4. d)Natural logic
Explanation
From book page 32 Answer Key: C. Topic 2.4 Propositional Logic (page 23): "Propositional logic is a basic form of logic used in computer science. It deals with statements that can be true or false. These statements are called propositions." Topic 2.8 (page 27): "Propositional logic deals with simple statements that are either true or false." Predicate logic goes further: it "uses predicates and variables to express detailed statements" (page 27).
153.
A compound proposition is:
Book exercise
1. a)(P)
2. b)(Q)
3. c)(P∧Q) Correct answer
4. d)True
Explanation
From book page 32 Answer Key: C. Topic 2.4, Simple and Compound Propositions (page 23): "A compound proposition is formed by combining two or more simple propositions. Logical connectives are used to join them. For example, "It is raining and it is cold" is a compound proposition." (P) and (Q) are single propositions; "True" is only a truth value. Note: the chapter writes the connective as the word AND and never explains the sign "∧"; "∧" means AND, so (P∧Q) is "P AND Q", two propositions joined by AND.
154.
The purpose of a truth table is to:
Book exercise
1. a)Write programs
2. b)Store data
3. c)Evaluate logical expressions Correct answer
4. d)Design algorithms
Explanation
From book page 32 Answer Key: C. Topic 2.5, Purpose of Truth Tables (page 25): "The main purpose of truth tables is to show how a logical expression behaves. They help us find when a statement is true or false." Opening of 2.5 (page 24): "They help in checking the correctness of logical expressions."
155.
A proposition that is true for at least one case is called:
Book exercise
1. a)Unsatisfiable
2. b)Invalid
3. c)Satisfiable Correct answer
4. d)Equivalent
Explanation
From book page 32 Answer Key: C. Topic 2.7, Conditions for a Proposition to be Satisfiable (page 26): "A proposition is satisfiable if there is at least one combination of truth values that makes it true. If all possible combinations make it false, it is unsatisfiable." DO YOU KNOW? (page 26): "A logical expression is satisfiable if there is at least one way to make it true."
156.
The symbol for the universal quantifier is:
Book exercise
1. a)∃
2. b)⟶
3. c)∧
4. d)∀ Correct answer
Explanation
From book page 32 Answer Key: D. Topic 2.9, Universal Quantifier (for all) (page 28): "The universal quantifier is used to indicate that a statement is true for all objects in a given set (as shown in Figure 2.8). It is denoted by the symbol "∀"." The symbol "∃" is the existential quantifier: "It is denoted by the symbol "∃"." (page 28).
157.
Predicate logic is mainly used to:
Book exercise
1. a)Draw diagrams
2. b)Represent relationships using variables Correct answer
3. c)Store numbers
4. d)Design networks
Explanation
From book page 32 Answer Key: B. Topic 2.8 Predicate Logic (page 27): "It allows us to express more detailed statements about objects and their properties. In predicate logic, we can talk about individuals, groups, and relationships between them (as shown in Figure 2.7)." Figure 2.7: Predicate Logic Structure shows the predicate Helps with two variables, x and y: Helps (x, y). Topic 2.10 (page 28) also uses predicates for relationships: Borrows(x, y) means "student x borrows book y".

2.1 Introduction to Computational Thinking

Computational thinking is mainly used for:

According to the book, computational thinking is:

According to the TIDBIT, computational thinking is used by scientists, engineers, and even ______ when planning complex tasks.

Computational thinking means thinking like a:

In computational thinking, the clear steps we create to solve a problem can be followed by:

In computational thinking, which of these do we do with unnecessary details?

According to the book, sorting books by subject or size shows:

According to the book, which activity includes breaking tasks into smaller parts?

According to the book, cooking a recipe uses:

According to the book, managing money needs:

In Figure 2.1: Computational Thinking in Daily Life, which step is labelled "Focus on What's Important"?

What is the LAST step shown in Figure 2.1: Computational Thinking in Daily Life?

2.2 Problem Solving Using Computational Thinking

The first step in problem solving is:

Breaking a large problem into smaller parts is called:

A step-by-step solution to a problem is known as an:

Problem solving using computational thinking helps us solve problems in a:

Problem solving using computational thinking helps reduce:

According to the DO YOU KNOW? box, computers solve problems in the way humans do when they use computational thinking, but:

When identifying a problem, it is important to know the given information and the:

While identifying a problem clearly, unnecessary details should be:

Which of these is a benefit of decomposition given in the book?

Why must the steps of a solution be in the correct order?

In Figure 2.2: Step by Step Algorithm Example, which step comes right after "Boil Water"?

According to the book, evaluation helps us check:

What shows whether a solution works properly?

According to the book, we can improve a solution by making it:

Arrange the four parts of problem solving in the order the book teaches them: (1) Evaluating and Improving Solutions, (2) Identifying a Problem Clearly, (3) Creating Step-by-Step Solutions, (4) Breaking a Problem into Smaller Parts (Decomposition).

2.3 Logic as a Knowledge Representation Framework

According to the book, logic is:

Logic helps computers:

Using logic, complex information can be represented:

In computer science, logic means:

Logic helps computers understand:

Logical statements are used in programs and algorithms. What do these statements help to do?

According to the book, logic helps computers think in a:

Using logic, decisions are made based on:

What does logic remove from reasoning and decision making?

Logic ensures that decisions are:

According to the book, logic is used in:

The TIDBIT says logic gives computers a way to "think" about facts and make decisions, almost like:

2.4 Propositional Logic

The logic that uses only true or false values is:

A compound proposition is:

A proposition is a statement that is:

Which of the following is NOT a proposition?

A proposition is usually represented by:

According to the book, propositions are:

"It is raining" is an example of a:

"It is raining and it is cold" is a:

A compound proposition is formed by:

Which logical connective is used when both statements must be true?

OR is used when:

NOT is used to:

According to Figure 2.4, "A or B" is true:

In Figure 2.3, the statement "1 > 3" is shown as:

According to the DO YOU KNOW? box, propositional logic is the simplest type of logic, but it:

2.5 Truth Tables

The purpose of a truth table is to:

A truth table lists:

The main purpose of truth tables is to:

For n propositions, a truth table has:

How many rows does the truth table for two propositions A and B have?

How many rows does a truth table need for three propositions P, Q and R?

In Figure 2.5, when A is True and B is False, A AND B is:

In Figure 2.5, A OR B is False only when:

In Figure 2.5, NOT A is True when:

Creating a truth table starts with:

While creating a truth table, logical connectives are applied:

Each proposition P or Q can take the value:

The truth value of a compound proposition is determined by:

Which of these is NOT a use of truth tables given in the book?

2.6 Propositional Equivalence

Propositional equivalence explains when two logical expressions:

Propositional equivalence is checked using:

Two expressions are equivalent if they have the same truth values:

Which symbol is used to show equivalence?

Even if two expressions look different, they may:

Besides truth tables, what else can help identify equivalence?