Division Tips and Tricks

Even Numbers

If a number is even, ending in 0, 2, 4, 6 or 8, it can always be divided by 2.

Numbers ending with 5 or 0

These always can be divided by 5. (Check out the 5 times table - 5,10,15,20,25 etc)

Numbers ending with 0

These can always be divided by 2,5 and 10.

Dividing by 2

Is the same as halving and is fairly easy for an even number - if the number is difficult or large, partition the number into hundreds, tens, units etc, then half them and add up the results.

574 ÷ 2 is 500 + 70 +4 ... divide by 2 gives 250 + 35 + 2 = 287

or split the number in a convenient way... 96 ÷ 2.
96 is the same as 80 + 16 ... divide by 2 gives 40 + 8 = 48

If the number is odd, ending with 1, 3, 5, 7 or 9, a useful technique is to subtract 1 from the number which is now even - half that number as above and then add on ½.

75 ÷ 2 ... 75 - 1 = 74 ... ½ of 74 is 37 ... add a ½ = 37½

Dividing by 3

Add up all the digits in the number to get a single number - if that number can be divided by 3, then the original number can also be divided by 3.

1458 ... add 1+4+5+8 = 18 (not a single number) so add 1+8 = 9
9 is divisible by 3 so 1458 is divisible by 3.

Dividing by 4

Is the same as dividing by 2 and then dividing by 2 again.

164 ÷ 4 .... 164 ÷ 2 = 82 then 82 ÷ 2 = 41

Dividing by 5

If the number ends in a 5 or a 0, then it can be divided by 5.

An easy method of dividing by 5, is to divide by 10 and then double the result.

430 ÷ 5 ... 430 ÷ 10 = 43 then 43 x 2 = 86

Dividing by 6

A number can be divided by 6 if it can be divided by 3 and is an even number.

258 ... 2 + 5 + 8 = 15 ... 1 + 5 = 6

Dividing by 7

To find out if a number can be divided by 7 - Take the last digit of the number and double it - then subtract the result from the first part of the number. If the answer is divisible by 7, then so is the original number.

392 ... 39(2) ... 2 x 2 = 4 ... 39 - 4 = 35 (which is divisible by 7)

Dividing by 8

Similar to 4, but do it again ... halve, then halve, then halve again.

184 ÷ 8 ... 184 ÷ 2 = 92 ... 92 ÷ 2 =46 ... 46 ÷ 3 = 23

Dividing by 9

Add up all the digits in the number to get a single number - if that number is 9, then it can be divided by 9.

675 ... 6 + 7 + 5 = 18 ... 1 + 8 = 9

Dividing by 10

If the number ends in 0 then it can be evenly divisible by 10.

To divide by 10, move all the digits 1 place to the right (see place value)

4525 becomes 452.5

or if the number is evenly divisible by 10, it will end in 0, so simply remove the 0.

340 becomes 34

Dividing by itself

A number that is divided by the same number is always 1.

2 ÷ 2 = 1 ... 10 ÷ 10 = 1 ... 100 ÷ 100 = 1 ... 12345 ÷ 12345 = 1

To check your division calculations

Use the inverse (opposite) - multiplication is the inverse of division.

After a division calculation, use multiplication to check your answer.

378 ÷ 7 = 54 ... check by multiplying 54 by 7 ... 54 x 7 = 378

 























CAT4 / 12 Pus papers