Divisibility Rules
- 1 → Any real number is divisible by 1.
- 2 → If the number is even, it is divisible by 2.
- 3 → Add up the digits of the number. If the sum is divisible by 3, the number is divisible by 3.
- 4 → If the last two digits are divisible by 4, the number is divisible by 4.
- 5 → If the number ends with a 5 or 0, it is divisible by 5.
- 6 → If the number is divisible by 2 and 3, it is divisible by 6.
- 7 → Double the last digit, then subtract it from the rest of the number. If the difference is divisible 7 or is 0, the number is divisible by 7.
- 8 → If the last 3 digits of the number are divisible by 8, the number is divisible by 8.
- 9 → Add up the digits of the number. If the sum is divisible by 9, the number is divisible by 9.
- 10 → If the number ends with a 0, it is divisible by 10.
- 11 → Add together every 2nd digit, starting from the left and subtract the sum of the rest of the numbers from that. If the difference is 0 or divisible by 11, the number is divisible by 11.
- 12 → If the number is divisible by 3 and 4, it is divisible by 12.
Divisibility Rules Example
Is 259,358,147 divisible by 3??
2+5+9+3+5+8+1+4+7=44 → add the digits in the number
44/3 is not divisible by 3, so 259,358,147 is not divisible by 3.
2+5+9+3+5+8+1+4+7=44 → add the digits in the number
44/3 is not divisible by 3, so 259,358,147 is not divisible by 3.
Divisibility Rules Practice Problem
Is 31,343,202 divisible by 11?
Answer Key
Answer Key