Curriculum
Grade XI Computer Science
Lessons
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Le-1 Computer System
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Le-2 Encoding Schemes and Number System
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le-3 Emerging Trends
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Le-4 Introduction to Problem Solving
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Le-5 Getting Started with Python
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Le-6 Flow of Control
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Le-7 Functions
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Le-8 Strings
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Le-9 Lists
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Le-10 Tuples and Dictionaries
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Le-11 Societal Impact
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Notes
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Work Sheets
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Le-4 Introduction to Problem Solving
School Revise · Class 11 Computer Science · Chapter 4
Introduction to Problem Solving
Code 083, Class 11. Before we write code, we plan. Here we learn the steps of solving a problem, and how to describe a solution using an algorithm, a flowchart and pseudocode.
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What this chapter is about
A computer only does what we tell it, so a clear plan comes first. In this chapter we learn the steps of problem solving and three ways to write a plan: an algorithm, a flowchart and pseudocode.
1. The steps of problem solving
Solving a problem with a computer follows clear steps: understand the problem, design a solution, write the code, then test and fix errors.
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The four steps: (1) understand and analyse the problem, (2) design an algorithm, (3) write the program, (4) test and debug (find and fix mistakes). |
2. Algorithms
An algorithm is a finite set of clear steps that solves a problem. It must be exact and end after a limited number of steps.
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Algorithm to add two numbers: Step 1 Start. Step 2 Read a and b. Step 3 sum = a + b. Step 4 Print sum. Step 5 Stop. |
3. Flowcharts
A flowchart draws the steps using symbols: an oval for start and stop, a parallelogram for input and output, a rectangle for a process, and a diamond for a decision, joined by arrows.
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4. Pseudocode and decomposition
Pseudocode writes the steps in plain, code-like words without a real programming language. Decomposition means breaking a big problem into smaller parts that are easier to solve.
Practise with the interactive
Drag the flowchart symbols into the right order for a simple task by tapping. The interactive opens right here in the lesson.
Practice set A, multiple choice
1. A finite set of clear steps to solve a problem is called an …
algorithm.
2. In a flowchart, a decision is shown by a …
diamond shape.
3. Finding and fixing mistakes in a program is called …
debugging.
4. Writing steps in plain, code-like words is called …
pseudocode.
Practice set B, short answer
1. Write an algorithm to find the sum of two numbers.
Start; read a and b; sum = a + b; print sum; Stop.
2. Name the flowchart symbols for start, input/output, process and decision.
Oval (start/stop), parallelogram (input/output), rectangle (process), diamond (decision).
3. What does decomposition mean in problem solving?
Breaking a big problem into smaller, easier parts.
Quick summary
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Problem solving has four steps: understand, design an algorithm, code, then test and debug. An algorithm is a finite set of clear steps. A flowchart draws them with symbols (oval, parallelogram, rectangle, diamond). Pseudocode writes them in plain code-like words, and decomposition breaks a big problem into smaller parts. |
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These free Class 11 Computer Science notes explain problem solving, algorithms, flowcharts and their symbols, pseudocode and decomposition, with a clear flowchart example and practice, for CBSE students across India and the Gulf including the UAE, Saudi Arabia, Qatar, Oman, Kuwait and Bahrain.
© 2026 School Revise. All rights reserved. Original content aligned to the CBSE and NCERT Class 11 Computer Science syllabus. Unauthorised copying is not permitted.
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