Prime Numbers
Numbers with exactly two factors: 1 and itself.
Quantitative Aptitude
The foundation of arithmetic — classification of numbers, divisibility rules, HCF & LCM, remainders, factorials, and unit digit cyclicity.
The number system is the arithmetic foundation section: classification of numbers, divisibility rules, prime factorization, HCF & LCM, remainders, factorials and unit-digit cyclicity. Most questions are formula-free — they reward knowing a few tables (divisibility rules, cyclicity cycles, factorial trailing-zero counts) and moving quickly between factors and multiples. HCF/LCM questions usually hide inside bells, toothed wheels, or product-of-numbers setups.
Integers, primes, composites, rationals, irrationals, and co-primes.
Numbers with exactly two factors: 1 and itself.
Tests to check if a number divides another without leaving a remainder.
Calculate sum of first n natural numbers.
The recurring question patterns in this topic — know the shape of each pattern before you solve.
Factor-based; HCF × LCM = product of two numbers.
HCF 12, product 1728 → LCM 144.
Quick divisibility checks for 2, 3, 4, 5, 8, 9, 11.
Sum-of-digits test for 3 and 9.
Remainder after division; break the divisor into factors.
N = 296k + 75 → remainder mod 37 is 1.
Digits repeat in cycles of 4 for most bases.
Unit digit of 7 power cycles 7, 9, 3, 1.
Count factors of 5 (and 25, 125…) in the factorial.
50! → 10 + 2 = 12 trailing zeros.
High-signal questions with full solution flow across difficulty patterns.
Classic exam problems worth internalizing — each one ships a complete step-by-step solution.
Unit digits repeat in cycles (period 2 or 4). Use power mod period to find unit digit.
Where most students lose marks — review these before you sit the test.
You have mastered the theory. Now put it under pressure with a focused topic test and instant explanations.
Take Number System Test