Lesson 1.1: Algorithms, Decomposition & Flowchart Symbols
Design unambiguous step-by-step algorithms and represent them visually using standard flowchart blocks.
⏱️ Reading Time: 15 mins
• ❓ 1 Interactive Practice Questions
What is an Algorithm?
An algorithm is a finite, ordered sequence of unambiguous instructions designed to solve a specific problem or perform a computation.
The Four Pillars of Computational Thinking
- Decomposition: Breaking a complex problem down into smaller, manageable sub-problems.
- Pattern Recognition: Identifying similarities or repeating trends across problems.
- Abstraction: Filtering out unnecessary details to focus on the core logic.
- Algorithmic Design: Creating step-by-step instructions to solve the problem.
Standard Flowchart Symbols
| Symbol Shape | Block Name | Purpose in Flowchart |
|---|---|---|
| Oval / Rounded Rectangle | Start / End (Terminator) | Marks the beginning or completion of an algorithm |
| Parallelogram | Input / Output | Reads user input or displays output results |
| Rectangle | Process | Performs a calculation or variable assignment |
| Diamond | Decision (Condition) | Evaluates a True/False condition (e.g., score ≥ 50) |
🎯 Key Learning Takeaways
• An algorithm must be finite, ordered, and unambiguous.
• Decomposition splits big problems into smaller parts.
• Diamond shapes represent True/False decision branches in flowcharts.
✍️ Lesson Practice Questions (1 Questions)
Solve these real-world challenges online, test your understanding, and reveal instant step-by-step explanations.
1
Multiple Choice
Easy
2 Marks
Which standard flowchart geometric shape is used to represent a Decision (True/False condition)?
A
Rectangle
B
Diamond
C
Oval
D
Parallelogram
💡 Click to View Correct Answer & Explanation ▼
Correct Answer:
B: Diamond
Step-by-Step Explanation:
A Diamond symbol represents a conditional branch (Yes/No or True/False decision) in standard flowcharts.