TELLING WHEN ONE NUMBER IS DIVISIBLE BY ANOTHER

You can learn to tell at a glance when a number is divisible by 2; 3; 4; 5; 6; 8; 9; 10 and/or 12. Here are the rules that will help you do this:

A number is divisible by 2 when it is even. For example: 4; 8; 56; and 316 are divisible by 2.

A number is divisible by 3 when the sum of its digits is divisible by 3. For example: 18, 123; 129; 138; 1 ,236 and 8,172,621 are divisible by 3.

A number is divisible by 4 when the last two digits of the number, when considered as a number, are divisible by 4. For example: 104; 208; 516; 720; 824 and 1,064 are divisible by 4.

A number is divisible by 5 when it ends in 5 or 0. For example: 45; 375; 925; 1,650; 1,800 and 1,555 are divisible by 5.

A number that is even and divisible by 3 is divisible by 6. For example: 18; 42; 204; 222 and 1,236 are divisible by 6.

A number is divisible by 8 when the last three digits of the number, when considered as a number, are divisible by 8. For example: 12,072; 3,168; 14,088 and 17,248 are divisible by 8.

A number is divisible by 9 when the sum of its digits are divisible by 9. For example: 927; 1,737; 6,786 and 18,765 are divisible by 9.

A number is divisible by 10 when the last digit of the number ends in 0. For example: 50; 110; 5,310; 34,670 and 45,810 are divisible by 10.

A number is divisible by 12 when it is divisible by both 3 and 4. For example: 924; 4,128; 51,624 and 6,708 are divisible by 12.