Ratio
Ratio is comparing something to something.
1) Say there is a fruit bowl and there is 3 oranges and 2 pears. The ratio would be :
Oranges : Pears Or Pears : Oranges
3 : 2 2 : 3
2) Now use the same ratio as the last example. You have 10 pears and you want to know how many oranges you have. Are you a bit stuck? Then follow my steps below:
Pears : Oranges
2 : 3
10 : ?
To get from 2 to 10, you times it by 5. You now need to times 3 x 5.
Pears : Oranges
2 : 3
10 : 15
Your new ratio is:
Pears : Oranges
10 : 15
3) I now have 20 plums and 12 bananas in a fruit bowl. I want you to simplify this. There is 2 methods.
Method 1
20 plums : 12 bananas
You know they can both be divided by 2. So, do 20 divided by 2 and 12 divided by 2.
20 plums : 12 bananas
10 plums : 6 bananas
You know they can both be divided by 2 AGAIN. So, divide 10 by 2 and divide 6 by 20
20 plums : 12 bananas
10 plums : 6 bananas
5 plums : 3 bananas
Your simplified ratio is 5 plums : 3 bananas
Method 2
20 plums : 12 bananas
You know they can both be divided by 4. So, do 20 divided by 4 and 12 divided by 4.
20 plums: 12 bananas
5 plums : 3 bananas
Your simplified ratio is 5 plums : 3 bananas.
You get the SAME answers in the end. Method 2 is quicker!
4) I now have 15 plums and 6 bananas in a fruit bowl. I want you to find out : If I had 1 plum how many bananas I would have. (This is a bit more difficult).
15 plums : 6 bananas
You know they can both be divided by 3. So, do 15 divided by 3 and 6 divided by 3.
5 plums : 2 bananas
You divide 5 by 5 so you get 1 as you need to find out how many bananas you would have if you had 1 plum. Then you need to divide 2 by 5.
1 plum: 0.4 bananas
Your answer would be : If you had 1 plum you would have 0.4 bananas.
Best Buys
This is where you work out sums to find out what is cheapest etc.
EG1)
What butter is best?
Small tub = 500g and it is 54p.
Family tub = 1kg and it is £1.06
Value size = 2kg and it is £1.95
You need to change the weight of all the butters so they are the same weight. You will then be able to see what butter is better by looking at the price. We will change them all to 1kg because that is the easiest way.
500g : 54p 1kg: £1.06 2kg : £1.95 Because they have all been
1kg : £1.08 1kg : 98p converted into 1kg the
(x2) (divide by 2) best butter is Family Tub.
EG2)
What amount of cereal is cheaper to buy?
200g : 80p
300g : £1.05
500g : £1.80
Looking at this you might think the 200g is cheaper but it isn't! First convert them all to the same weight. 100g is the easiest way.
200g : 80p 300g : £1.05 500g : £1.80
100g : 40p 100g : 35p 100g : 36p
(divide by 2) (divide by 3) (divide by 5)
The cheapest one is 300g because for every 100g it is only 35p.
Ratio is comparing something to something.
1) Say there is a fruit bowl and there is 3 oranges and 2 pears. The ratio would be :
Oranges : Pears Or Pears : Oranges
3 : 2 2 : 3
2) Now use the same ratio as the last example. You have 10 pears and you want to know how many oranges you have. Are you a bit stuck? Then follow my steps below:
Pears : Oranges
2 : 3
10 : ?
To get from 2 to 10, you times it by 5. You now need to times 3 x 5.
Pears : Oranges
2 : 3
10 : 15
Your new ratio is:
Pears : Oranges
10 : 15
3) I now have 20 plums and 12 bananas in a fruit bowl. I want you to simplify this. There is 2 methods.
Method 1
20 plums : 12 bananas
You know they can both be divided by 2. So, do 20 divided by 2 and 12 divided by 2.
20 plums : 12 bananas
10 plums : 6 bananas
You know they can both be divided by 2 AGAIN. So, divide 10 by 2 and divide 6 by 20
20 plums : 12 bananas
10 plums : 6 bananas
5 plums : 3 bananas
Your simplified ratio is 5 plums : 3 bananas
Method 2
20 plums : 12 bananas
You know they can both be divided by 4. So, do 20 divided by 4 and 12 divided by 4.
20 plums: 12 bananas
5 plums : 3 bananas
Your simplified ratio is 5 plums : 3 bananas.
You get the SAME answers in the end. Method 2 is quicker!
4) I now have 15 plums and 6 bananas in a fruit bowl. I want you to find out : If I had 1 plum how many bananas I would have. (This is a bit more difficult).
15 plums : 6 bananas
You know they can both be divided by 3. So, do 15 divided by 3 and 6 divided by 3.
5 plums : 2 bananas
You divide 5 by 5 so you get 1 as you need to find out how many bananas you would have if you had 1 plum. Then you need to divide 2 by 5.
1 plum: 0.4 bananas
Your answer would be : If you had 1 plum you would have 0.4 bananas.
Best Buys
This is where you work out sums to find out what is cheapest etc.
EG1)
What butter is best?
Small tub = 500g and it is 54p.
Family tub = 1kg and it is £1.06
Value size = 2kg and it is £1.95
You need to change the weight of all the butters so they are the same weight. You will then be able to see what butter is better by looking at the price. We will change them all to 1kg because that is the easiest way.
500g : 54p 1kg: £1.06 2kg : £1.95 Because they have all been
1kg : £1.08 1kg : 98p converted into 1kg the
(x2) (divide by 2) best butter is Family Tub.
EG2)
What amount of cereal is cheaper to buy?
200g : 80p
300g : £1.05
500g : £1.80
Looking at this you might think the 200g is cheaper but it isn't! First convert them all to the same weight. 100g is the easiest way.
200g : 80p 300g : £1.05 500g : £1.80
100g : 40p 100g : 35p 100g : 36p
(divide by 2) (divide by 3) (divide by 5)
The cheapest one is 300g because for every 100g it is only 35p.