__Divisibility Rules__

__Divisibility Rules__

There are tricks to help you determine if a number is divisible by 2, 3, 4, 5, 6, 9, and 10. Use these quick tricks instead of dividing to find factors.

2- any even number (a number ending in 0, 2, 4, 6, 8) is divisible by 2

example - 74

4 - if the numbers in the tens and ones place is divisible by 4, then the whole number is divisible by 4.

example - 7

5 - any number ending in 5 or 0 is divisible by 5

example - 63

example - 96

10 - any number ending in 0 is divisible by 10

example - 619,95

These rules involve some work; you cannot just look at the number to determine divisibility.

3 - if the sum of the digits is divisible by 3, then the original number is divisible by 3

example - 252....2 + 5 +2 =

6 - if a number is divisible by BOTH 2 AND 3, then the number is divisible by 6.

example - 13

9 - if the sum of the digits is divisible by 9, then the original number is divisible by 9.

example - 963.....9 + 6 + 3 = 18 is divisible by 9, therefore 963 is divisible by 9.

__Rules and Examples____Easy, "Look-at-the-Number" Divisibility Rules__2- any even number (a number ending in 0, 2, 4, 6, 8) is divisible by 2

example - 74

__6__is divisible by 2 because it ends in 64 - if the numbers in the tens and ones place is divisible by 4, then the whole number is divisible by 4.

example - 7

__16__......16 is divisible by 4, therefore 716 is divisible by 4.5 - any number ending in 5 or 0 is divisible by 5

example - 63

__0__is divisible by 5 because it ends in 0example - 96

__5__is divisible by 5 because it ends in 510 - any number ending in 0 is divisible by 10

example - 619,95

__0__is divisible by 10 because it ends in 0__"Work-for-it" Divisibility Rules__These rules involve some work; you cannot just look at the number to determine divisibility.

3 - if the sum of the digits is divisible by 3, then the original number is divisible by 3

example - 252....2 + 5 +2 =

__9__is divisible by 3, therefore, 252 is divisible by 3.6 - if a number is divisible by BOTH 2 AND 3, then the number is divisible by 6.

example - 13

__8__- 8 is even, so it is divisible by 2.....1 + 3 + 8 = 12 is divisible by 3. Since 138 is divisible by 2 and 3, then it is divisible by 6.9 - if the sum of the digits is divisible by 9, then the original number is divisible by 9.

example - 963.....9 + 6 + 3 = 18 is divisible by 9, therefore 963 is divisible by 9.