JEE Main Maths · Relations and Functions

Number of Injective Functions

Number of Injective Functions (Relations and Functions) was asked 3 times in 3 JEE Main shifts, 2022–2026, out of the 42 shifts Lumi analysed. 2 of the 3 had a numerical answer.

Times asked: 3; in 3 shifts
Years: 2022–2026
Usual format: Numerical value; Multi-step
Pattern: Frequent; repeats across shifts

How it is asked

Count injective functions with constraints
Count of one-one functions

Difficulty

Easy 0Medium 2Hard 1

Where it sits

Chapter: Relations and Functions. Topic: Permutations and Combinations, 50 questions over 22 ideas.

All 3 questions

Newest first, each with its options and official answer.

5 Apr 2026, Shift 1 · Q21Let $A = \{1, 2, 3, 4, 5, 6\}$ . The number of one-one functions $f: A \to A$ such that $f(1) \geq 3$ , $f(3) \leq 4$ and $f(2) + f(3) = 5$ ,…MediumNumerical value
8 Apr 2024, Shift 1 · Q1Let $[t]$ be the greatest integer less than or equal to $t$ . Let $A$ be the set of all prime factors of 2310 and $f: A \to \mathbb{Z}$ be…MediumSingle correct
24 Jun 2022, Shift 1 · Q21The number of one-one functions $f:\{a, b, c, d\}\to\{0, 1, 2, \ldots, 10\}$ such that $2f(a)-f(b)+3f(c)+f(d)=0$ is ______.HardNumerical value