Home › coding › aptitude › apt number system

Apt Number System — Free Aptitude Tutorial

Learn Apt Number System in Aptitude with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.

✓ 100% Free ✓ No Login Needed ✓ NCERT / CBSE Aligned ✓ Download as PDF

TL;DR: Learn Apt Number System in Aptitude with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.

Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated Jul 14, 2026

🤖 Stuck on any question? Ask Syllab's free AI Tutor for a step-by-step explanation — instant, unlimited, no login.

Apt Number System in Aptitude

Numbers are classified into Natural Numbers (1,2,3...), Whole Numbers (0,1,2...), Integers (...-2,-1,0,1,2...), Rational Numbers (p/q form), Irrational Numbers (√2, π), and Real Numbers.

Even Numbers are divisible by 2 (2,4,6...). Odd Numbers are not (1,3,5...). Prime Numbers have exactly two factors: 1 and itself (2,3,5,7,11...). Composite Numbers have more than two factors.

Divisibility Rules: A number is divisible by 2 if last digit is 0,2,4,6,8. By 3 if sum of digits is divisible by 3. By 4 if last two digits form a number divisible by 4. By 5 if last digit is 0 or 5. By 9 if digit sum is divisible by 9.

HCF (Highest Common Factor) is the largest number that divides two or more numbers exactly. LCM (Least Common Multiple) is the smallest number exactly divisible by each of the given numbers. HCF × LCM = Product of two numbers.

Learn Apt Number System step by step with Syllab's free interactive Aptitude tutorial — runnable code examples, practice exercises and instant AI feedback, all free with no signup. Explore the full Aptitude course →

Explore:

  • Syllabus
  • Practice
  • Mock Tests
  • NCERT Solutions
  • Coding
  • GK Quiz
  • Career Predictor
  • AI Tutor
  • Live Quiz
  • Doubt Solver
  • Microlearning
  • Free Alternatives
  • Kids Zone
  • Study Room
  • Calculators
  • Worksheets

Syllab.in — Free learning for Indian students, Class 1–12