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.

Pick a unit

CS2 Computer Hardware

This unit carries about 12 marks in the paper. We split it into 24 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 22 of them. 2 were never asked. The top 5 topics make 40% of all the times this unit was asked. Last asked: 2026.

22asked by the board at least once

2in the syllabus, never asked

55times a topic of this unit was asked

3.5hours for one attempt at every topic

What the papers ask most

  • Define encoder, decoder, multiplexer and state uses6 times, last 2026
  • Derive and reduce the expression of a given logic circuit5 times, last 2026
  • Encoder vs decoder; decoder vs multiplexer5 times, last 2024
  • Symbol, truth table and expression of the seven gates3 times, last 2025
  • Output of gates or a gate chain for given inputs3 times, last 2025
  • Half adder: use, truth table, SUM and CARRY, circuit3 times, last 2025 improvement
  • Octal to binary (8:3) encoder circuit and working3 times, last 2025 improvement
  • Reduced SOP as NAND-only, POS as NOR-only circuit3 times, last 2025
  • Draw the AND-OR or OR-AND circuit of a reduced expression3 times, last 2024
  • Draw the full adder circuit (SUM and CARRY)3 times, last 2023

In the syllabus, never asked (2)

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

  • Switching circuit for a Boolean expression and backDiagram
  • Why NAND and NOR are universal gatesGive reason

All the topics in Computer Science: Computer Hardware →

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