ISC Class 12 Computer Science Important Topics 2027
Last updated:
Every topic ranked by how often and how recently it was asked in 4 board + 3 official sample papers (2023–2026). Teal tags = board papers, orange tags = official sample papers.
Top 10 most important topics
| # | Topic | Chapter | Asked in | Importance |
|---|---|---|---|---|
| 1 | Minterms, maxterms, canonical and cardinal forms | Boolean Algebra | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024 | ★★★★★ |
| 2 | Laws and theorems of Boolean algebra | Boolean Algebra | Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| 3 | Complement of a Boolean expression (De Morgan's theorem) | Boolean Algebra | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| 4 | Principle of duality | Boolean Algebra | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| 5 | Address calculation (row major and column major) | Arrays | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| 6 | Tracing a recursive function (output and purpose) | Recursion | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| 7 | Karnaugh map reduction (SOP) | Boolean Algebra | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| 8 | Karnaugh map reduction (POS) | Boolean Algebra | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| 9 | Truth table and SOP/POS expression from a word problem | Boolean Algebra | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| 10 | Number-based class program using a recursive method | Recursion | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
Chapter-wise important topics
Propositional Logic · Boolean Algebra and Computer Hardware
| Converse, inverse and contrapositive asked 6× | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2025 | ★★★☆☆ |
| Verifying validity of a proposition using a truth table asked 4× | Board 2025Sample 2023Sample 2024Sample 2025 | ★★☆☆☆ |
| Tautology, contradiction and contingency asked 3× | Board 2023Board 2024Board 2026 | ★☆☆☆☆ |
| Propositional connectives and well-formed formulae asked 1× | Sample 2024 | ★☆☆☆☆ |
| Law of implication and biconditional asked 1× | Board 2026 | ★☆☆☆☆ |
| Chain rule and modus ponens asked 1× | Board 2026 | ★☆☆☆☆ |
| Equivalence laws of propositional logic asked 1× | Board 2025 | ★☆☆☆☆ |
Boolean Algebra · Boolean Algebra and Computer Hardware
| Minterms, maxterms, canonical and cardinal forms asked 12× | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024 | ★★★★★ |
| Laws and theorems of Boolean algebra asked 7× | Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| Complement of a Boolean expression (De Morgan's theorem) asked 7× | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| Principle of duality asked 7× | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| Karnaugh map reduction (SOP) asked 7× | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| Karnaugh map reduction (POS) asked 7× | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| Truth table and SOP/POS expression from a word problem asked 7× | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| Simplification using Boolean laws asked 4× | Board 2023Board 2024Sample 2023Sample 2025 | ★★☆☆☆ |
Computer Hardware · Boolean Algebra and Computer Hardware
| Half adder and full adder asked 5× | Board 2023Board 2026Sample 2023Sample 2024Sample 2025 | ★★☆☆☆ |
| Deriving the Boolean expression from a logic circuit asked 5× | Board 2023Board 2025Board 2026Sample 2024Sample 2025 | ★★☆☆☆ |
| Elementary logic gates and their outputs asked 5× | Board 2023Board 2024Board 2025Sample 2023Sample 2025 | ★★☆☆☆ |
| Decoders asked 4× | Board 2024Board 2026Sample 2023Sample 2025 | ★★☆☆☆ |
| Encoders asked 2× | Board 2025Sample 2024 | ★☆☆☆☆ |
| NAND and NOR as universal gates asked 2× | Board 2024Board 2026 | ★☆☆☆☆ |
| Multiplexers asked 2× | Board 2023Sample 2024 | ★☆☆☆☆ |
Primitive Values, Variables and Statements · Java Programming
| Output tracing of iterative code asked 2× | Board 2023Sample 2023 | ★☆☆☆☆ |
| Loops, break and continue asked 1× | Board 2025 | ★☆☆☆☆ |
Methods · Java Programming
| Completing missing code in a method asked 5× | Board 2024Board 2025Board 2026Sample 2024Sample 2025 | ★★☆☆☆ |
| Static methods and static/instance variables asked 4× | Board 2024Board 2026Sample 2024Sample 2025 | ★★☆☆☆ |
| The this keyword asked 2× | Board 2023Board 2025 | ★☆☆☆☆ |
| Formal and actual arguments; return statement asked 1× | Board 2026 | ★☆☆☆☆ |
Arrays · Java Programming
| Address calculation (row major and column major) asked 7× | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| Combining arrays using objects asked 3× | Board 2026Sample 2023Sample 2025 | ★★☆☆☆ |
| Double-dimensional array (matrix) programs asked 3× | Board 2023Board 2025Sample 2024 | ★☆☆☆☆ |
| Sorting techniques (bubble, selection, insertion) asked 1× | Board 2024 | ★☆☆☆☆ |
Strings · Java Programming
| Character-by-character word manipulation asked 5× | Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| String class methods and immutability asked 1× | Sample 2025 | ★☆☆☆☆ |
| ASCII value based processing asked 1× | Board 2024 | ★☆☆☆☆ |
| Sentence and word processing asked 1× | Board 2023 | ★☆☆☆☆ |
Recursion · Java Programming
| Tracing a recursive function (output and purpose) asked 7× | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| Number-based class program using a recursive method asked 7× | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| Recursion versus iteration asked 2× | Board 2026Sample 2025 | ★☆☆☆☆ |
| Base case and the call stack asked 1× | Board 2024 | ★☆☆☆☆ |
Inheritance, Interfaces and Polymorphism · Inheritance, Data Structures and Complexity
| Subclass program using inheritance (super class assumed) asked 7× | Board 2023Board 2024Board 2025Board 2026Sample 2023Sample 2024Sample 2025 | ★★★☆☆ |
| Interfaces in Java asked 5× | Board 2023Board 2024Board 2026Sample 2023Sample 2024 | ★★☆☆☆ |
| Types of inheritance asked 2× | Board 2023Sample 2023 | ★☆☆☆☆ |
| Super and derived classes; the super keyword asked 1× | Sample 2023 | ★☆☆☆☆ |
Stacks and Queues · Inheritance, Data Structures and Complexity
| Infix to postfix conversion asked 4× | Board 2024Board 2025Sample 2023Sample 2024 | ★★☆☆☆ |
| Infix to prefix conversion asked 3× | Board 2023Board 2026Sample 2025 | ★☆☆☆☆ |
| Queue implementation using a class asked 2× | Sample 2023Sample 2024 | ★☆☆☆☆ |
| Double ended queue (dequeue) asked 2× | Board 2023Sample 2025 | ★☆☆☆☆ |
| Stack implementation using a class asked 2× | Board 2024Board 2026 | ★☆☆☆☆ |
| Circular queue asked 1× | Board 2025 | ★☆☆☆☆ |
Linked Lists and Binary Trees · Inheritance, Data Structures and Complexity
| Linked list algorithm/method (insert, delete, search, traverse) asked 5× | Board 2023Board 2025Board 2026Sample 2023Sample 2025 | ★★☆☆☆ |
| Binary tree terminology (root, leaves, level, depth, size, degree, siblings) asked 4× | Board 2024Board 2025Sample 2024Sample 2025 | ★★☆☆☆ |
| Binary tree traversals (pre-order, in-order, post-order) asked 3× | Board 2023Board 2026Sample 2023 | ★☆☆☆☆ |
| Linked list concepts asked 2× | Board 2023Sample 2023 | ★☆☆☆☆ |
Complexity and Big O Notation · Inheritance, Data Structures and Complexity
| Big O notation of loops/code segments asked 3× | Board 2025Board 2026Sample 2025 | ★★☆☆☆ |
| Dominant term and constant factors asked 2× | Board 2024Sample 2024 | ★☆☆☆☆ |
Importance = how often a topic was asked × how recent, with extra weight for the latest official sample paper.