My bike’s fuel has a ratio of oil to petrol 1 : 25 Sounds complicated

Using the simplest ratio to describe different quantities. Sue is explaining how to use a ratio to describe red and green hearts.

Count the number of red and green hearts 4 RED and 8 GREEN Record the numbers using headings like this Red : Green 4 : 8 The : says ‘to’

Try to write the ratio in its simplest terms Red : Green 4 : 8 2 : 4 1 : 2 Divide ÷ by 2

The ratio of red to green is Red : Green 1 : 2 This tells you that there are 2 green hearts for every red heart

Copy and complete this chart Ratio Simplest terms 12 : 16 24 : 32 27 : 36 28 : 40

Copy and complete this chart Ratio Simplest terms 12 : 16 3 : 4 24 : 32 27 : 36 28 : 40 7 : 10

For example, share 36 into the ratio 2 : 7 Sharing a quantity into a given ratio For example, share 36 into the ratio 2 : 7 First ADD the ratio 2 + 7 = 9 Second DIVIDE this answer into the quantity to be shared 36 ÷ 9 = 4 Third MULTIPLY the ratio by this answer 2 X 4 : 7 X 4 This is the answer 8 : 28

+ ÷ X To share into a given ratio, the things to do are: Share 32 into the the ratio 3 : 5 3 + 5 = 8 32 ÷ 8 = 4 3 X 4 = 12 : 5 X 4 = 20 Answer 12 : 20

Share these into the given ratio Quantity Share 2 : 3 50 2 : 5 28 3 : 7 20 4 : 5 360 1 : 2 : 5 32

Share these into the given ratio Quantity Share 2 : 3 50 20 : 30 2 : 5 28 8 : 20 3 : 7 20 6 : 14 4 : 5 360 160 : 200 1 : 2 : 5 32 4 : 8 : 20

Finding an unknown number that fits a given ratio Example – If the ratio of red beads black beads is 3 : 5, how many black beads will I need for 21 red beads? Red : Black 3 : 5 21 : ?

First find the number that you multiply 3 by to get 21 Red : Black 3 : 5 21 : ? X 7

Red : Black 3 : 5 21 : 42 X 7 X 7

Red : Black 2 : 7 12 : ? Another Example 2 X 6 is 12 so you multiply 7 by 6 to get the ? X 6

Red : Black 2: 7 12 : 42 X 6 X 6