Whole Number Division

• Only even numbers are divisible by 2.
• A number is divisible by 3 if the sum of the digits is in the three times table.
• If the last 2 digits of a number are in the four times table then it is divisible by 4.
• Only numbers ending in 0 or 5 are divisible by 5.
• For a number to be divisible by 6, it has to be divisible by 2 AND 3.
• The divisibility test for 7 is the hardest – take the last digit, multiply it by 2 and subtract from the other digits. If the answer is zero or in the seven times table then it is divisible by 7.
• Only the last three digits of a number need to be divisible by 8.
• A number is divisible by 9 if the sum of the digits is in the nine times table.

Knowing these divisibility tests can even help you with long division. If you have to divide by a number greater than 10, see if you can break it into its factors. Then perform repeated division until you reach an answer. So, if you are asked to divide a number by 24, you could divide it by 4, and then divide the result by 6. This is much easier, and less likely to result in mistakes, than the traditional long division method!