my math world

Monday 26 November 2012

Division Tips


Division tips


When dividing numbers you'll start to notice lots of patterns. Here are some common patterns and ways of dividing that will soon help you get to grips with splitting up numbers. 

A number is divisible by another number if there is no remainder when you divide.

Even numbers: 
If a number is even it’s always divisible by 2.
Even numbers end in 0, 2, 4, 6, or 8.

Numbers that end in 0 or 5: 
If a number ends in 0 or 5 it’s always divisible by 5.

Numbers that end in 0:
If a number ends in 0 it’s always divisible by 2, 5 and 10.

What other division patterns can you find?

Dividing by 2: 
Dividing by 2 is the same as halving a number. A quick method is to split the number into tens and units and halve:

74 ÷ 2 is half of 70, which is 35 plus half of 4, which is 2.
If you add together 35 and 2 it gives you the answer: 37.

You can also split the numbers up to make it easier to halve. For example:
74 is the same as 60 + 14. So:
74 ÷ 2 is half of 60, which is 30 plus half of 14, which is 7.
If you add together 30 and 7 it gives you the answer: 37.

Dividing by 4: 
Remember that 2 × 2 = 4. Dividing by 4 is the same as halving
and halving again:
48 ÷ 4 is half of 48, which is 24 and half of 24, which is 12.

Dividing by 10: 
To divide by 10 move all the numbers one place value to the right:
90 ÷ 10 = 9

Splitting into factors: 
You can split numbers into factors to make them easier to divide:
90 ÷ 6 = (90 ÷ 3) ÷ 2 = 30 ÷ 2 = 15

Checking your calculations
Multiplication and division are linked. They are the opposite action of each other:
10 × 5 = 50, 50 ÷ 5 = 10 or 50 ÷ 10 = 5

When you carry out a division you can check your answer using multiplication.

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