Chapter 2 · Computational Thinking & Algorithms

2.2Problem Solving Using Computational Thinking

Four steps to solve any problem: identify it clearly, break it into parts, write an algorithm, then test and improve it.

Written and checked by Muhammad Raheel(opens in a new tab)

Full Stack Developer · AI Engineer · Reviewed 21 Oct 2026 · 3 min read

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In topic 2.1 you met computational thinking. Now you use it as a method. Topic 2.2 gives four steps that take you from a confusing problem to a correct, tested answer. Working this way keeps your thinking logical and organized, and it cuts down mistakes and confusion.

Identifying a Problem Clearly

Before you solve anything, be sure you know what is being asked. This comes first, and the book calls it the most important step.

Find two things: the information you are given, and the result you are expected to produce. Ask yourself simple questions about the problem. Drop any detail that does not affect the answer. A clear problem saves time and leads to a correct solution.

Breaking a Problem into Smaller Parts (Decomposition)

A big problem is hard to solve in one go. So you split it.

Small parts are easier to understand and to manage. You solve them one by one, so you feel less confused and less stressed. Decomposition also keeps your thoughts organized, because you work on one task at a time. Computer scientists use it all the time, and so do people in daily life.

Creating Step-by-Step Solutions

Next, you write the solution as a list of steps.

Good steps are clear and simple. They must also come in the correct order, because the wrong order causes errors. When the steps are written well, anyone can use them, and a computer can follow them too.

The book shows this with Figure 2.2, "Step by Step Algorithm Example": making a cup of tea.

Figure 2.2 redrawn: a flowchart with numbered arrows, Start, Boil Water, Steep Tea, Add Milk or Lemon, Serve Tea, End, and a key points box

Try swapping two boxes. If you "Serve Tea" before you "Boil Water", you get an empty cup. Order matters.

Evaluating and Improving Solutions

Finding an answer is not the end. You check it. Evaluation tells you whether the solution is correct, and it helps you find and fix mistakes. Testing shows whether the solution really works.

Then you make it better. A solution can be improved by making it simpler or faster. Each mistake you fix teaches you something, and better solutions give better performance.

Practice this topic

All MCQs of this chapter with answers

Short questions

1.What is decomposition in problem solving?2 marks
Answer
From the book: "Breaking a problem into smaller parts is called decomposition. A big problem can be difficult to solve at once. Smaller parts are easier to understand and manage. Each part can be solved step by step."
2.What is an algorithm?2 marks
Answer
From the book: "Creating step-by-step solutions helps us solve problems in an organized way. These steps are known as algorithms. Each step should be clear and simple to follow. The steps must be in the correct order." Chapter Summary (page 30): "An algorithm is a step-by-step set of instructions used to solve a problem or perform a task."
3.Why is identifying a problem clearly important?2 marks
Answer
From the book: "Identifying a problem clearly is the first and most important step in problem solving." "A clear problem leads to a correct solution. This step helps save time and effort. Clear thinking makes problem solving easier."
4.What should we do to identify a problem clearly?2 marks
Answer
From the book: "We must understand what the problem is asking. It is important to know the given information and the expected result. Asking simple questions helps in understanding the problem better. Unnecessary details should be ignored."
5.How does decomposition help us solve a problem?2 marks
Answer
From the book: "Smaller parts are easier to understand and manage. Each part can be solved step by step. This reduces confusion and stress. Decomposition helps us organize our thoughts. It allows us to focus on one task at a time."
6.Write the steps of Figure 2.2: Step by Step Algorithm Example in the correct order.2 marks
Answer
From Figure 2.2 (page 22): Start, Boil Water, Steep Tea, Add Milk or Lemon, Serve Tea, End. The book says: "Computers also follow step-by-step instructions (as shown in Figure 2.2)."
7.Why is it important to evaluate a solution?2 marks
Answer
From the book: "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. Testing the solution shows whether it works properly."
8.How can a solution be improved, and what is the benefit?2 marks
Answer
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."

Long questions

1.Describe the steps involved in problem solving using computational thinking. Explain decomposition with an example.8 marks
Answer
The steps are the four sub-headings of topic 2.2, in book order (pages 21 to 22):
1. Opening: "Problem solving using computational thinking helps us solve problems in a logical and organized way. It helps reduce mistakes and confusion."
2. Identifying a Problem Clearly: "Identifying a problem clearly is the first and most important step in problem solving. We must understand what the problem is asking. It is important to know the given information and the expected result." "Unnecessary details should be ignored. A clear problem leads to a correct solution."
3. Breaking a Problem into Smaller Parts (Decomposition): "Breaking a problem into smaller parts is called decomposition. A big problem can be difficult to solve at once. Smaller parts are easier to understand and manage. Each part can be solved step by step. This reduces confusion and stress." "It allows us to focus on one task at a time. This method is widely used in computer science and daily activities."
4. Creating Step-by-Step Solutions: "These steps are known as algorithms. Each step should be clear and simple to follow. The steps must be in the correct order. This prevents errors during problem solving." Figure 2.2: Step by Step Algorithm Example: Start, Boil Water, Steep Tea, Add Milk or Lemon, Serve Tea, End.
5. Evaluating and Improving Solutions: "After finding a solution, it is important to evaluate it. Evaluation helps us check if the solution is correct." "Testing the solution shows whether it works properly. We can improve the solution by making it simpler or faster."
6. Decomposition example from the book: topic 2.1 (page 21) says "Planning a trip includes breaking tasks into smaller parts.", and Figure 2.1 shows "1. Decomposition, Break Down the Problem". Note: topic 2.2 itself gives no worked example of decomposition, so use the book's trip example and show its smaller parts in your own words.
Aim for 250-350 words.
2.Explain how step-by-step solutions are created and why solutions must be evaluated and improved. Use Figure 2.2 in your answer.8 marks
Answer
Cover the last two sub-headings of 2.2 (pages 21 to 22):
1. Creating Step-by-Step Solutions: "Creating step-by-step solutions helps us solve problems in an organized way. These steps are known as algorithms. Each step should be clear and simple to follow. The steps must be in the correct order. This prevents errors during problem solving. Anyone can understand and use the steps easily."
2. Figure 2.2: Step by Step Algorithm Example: Start, Boil Water, Steep Tea, Add Milk or Lemon, Serve Tea, End. "Computers also follow step-by-step instructions (as shown in Figure 2.2). Good planning leads to correct results."
3. 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. Testing the solution shows whether it works properly."
4. Improving: "We can improve the solution by making it simpler or faster. This process helps us learn from errors. Improving solutions leads to better performance. Evaluation is an important part of problem-solving."
Aim for 200-300 words.

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