🎯 Goal
Understand when one number is divisible by another and learn divisibility rules.
📖 Lesson Description
A number \(a\) is divisible by another number \(b\) if dividing \(a\) by \(b\) leaves no remainder. We write \(b | a\).
🔎 Divisibility Rules
- 2 → last digit is even (0,2,4,6,8)
- 3 → sum of digits divisible by 3
- 5 → last digit 0 or 5
- 10 → last digit 0
📠Examples
- 12 ÷ 3 = 4 → divisible by 3
- 25 ÷ 5 = 5 → divisible by 5
- 14 ÷ 2 = 7 → divisible by 2
- 14 ÷ 3 = 4 remainder 2 → not divisible by 3
âœï¸ Practice
- Is 36 divisible by 6?
- Is 45 divisible by 5?
- Is 27 divisible by 3?
- Is 28 divisible by 4?