Computational Thinking

The three techniques

• Decomposition – break a big problem into smaller, manageable sub-problems.
• Abstraction – remove unnecessary detail to focus on what matters (a map shows roads, not every brick).
• Algorithmic thinking – design clear step-by-step rules to solve the problem.

Pseudocode

Structured English-like code, not tied to one language:

total ← 0
FOR i ← 1 TO 5
    total ← total + i
NEXT i
OUTPUT total

Flowchart symbols

Symbol	Meaning
Oval	Start / Stop
Parallelogram	Input / Output
Rectangle	Process
Diamond	Decision (Yes/No)
Arrow	Flow direction

Exam tip

"Decompose" → list the separate sub-tasks. "Use abstraction" → state which details you ignored and why. Pseudocode doesn't need to be perfect syntax, but it must be logically clear.