What the board asks

We went through the ISC board papers, question by question, and matched each question to a topic. Here is what was asked, how often, and what was never asked.

Computer Science: 180 topics in the 2027 syllabus, across 10 units. The board has asked 117 of them at least once. 63 were never asked in the papers we checked.

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CS10 Complexity and Big O Notation

This unit carries about 3 marks in the paper. We split it into 9 topics: each is one thing an examiner can ask, and you can practise it on paper in 5 to 25 minutes. The board has asked 6 of them. 3 were never asked. The top 5 topics make 88% of all the times this unit was asked. Last asked: 2026.

6asked by the board at least once

3in the syllabus, never asked

8times a topic of this unit was asked

1hours for one attempt at every topic

What the papers ask most

  • Big O of sequential and nested loops3 times, last 2025 improvement
  • Big O of dependent and halving or doubling loopsonce, last 2026
  • Dominant term and dropping constantsonce, last 2024
  • Best and worst case Big O of searching and sortingonce, last 2020
  • Compare growth rates such as O(n^2) and O(2^n)once, last 2019
  • Define complexity and Big O; factors of complexityonce, last 2018

In the syllabus, never asked (3)

They can still come, because they are in the syllabus. Give each one clean attempt. Your plan has two practice questions for each.

  • Best, average and worst caseStatement
  • Complexity of code that calls methodsSum
  • Complexity of matrix and linear-equation algorithmsSum

All the topics in Computer Science: Complexity and Big O Notation →

The 10 topics Computer Science papers ask most

Counted on the board papers from 2018 to the 2027 specimen paper, which every unit has been checked against.

  1. 1.Principle of duality: state it and write the dualCS1 Boolean Algebra · asked 8 times since 2018
  2. 2.Complement of an expression using De Morgan's theoremCS1 Boolean Algebra · asked 8 times since 2018
  3. 3.Word problem to truth table and SOP or POSCS1 Boolean Algebra · asked 8 times since 2018
  4. 4.K-map reduction of a four-variable POS expressionCS1 Boolean Algebra · asked 8 times since 2018
  5. 5.Pre-order, in-order and post-order traversalCS9 Data Structures · asked 8 times since 2018
  6. 6.K-map reduction of a four-variable SOP expressionCS1 Boolean Algebra · asked 7 times since 2018
  7. 7.Read a tree: leaves, internal nodes, parent, siblings, degreeCS9 Data Structures · asked 7 times since 2018
  8. 8.Truth table to classify tautology, contradiction or contingencyCS1 Boolean Algebra · asked 6 times since 2018
  9. 9.Convert between cardinal and canonical formsCS1 Boolean Algebra · asked 6 times since 2018
  10. 10.Address of an element, row major and column majorCS6 Arrays and Strings · asked 6 times since 2018

See when each unit comes in your plan