This worksheet is about proportion.
Here is a recipe for 12 flapjacks.
 8 oz butter
 6 oz sugar
 6 oz porridge oats
To find the quantities needed for 8 flapjacks, we first find how much is needed for 1 flapjack.
For 1 flapjack, divide each quantity by 12.
You need 

= 

oz butter  

= 

oz sugar and 

oz oats. 
For 8 flapjacks, multiply each of these quantities by 8.
You need 

× 8 = 

= 5 

oz butter  

× 8 =  4 oz sugar and 4 oz oats. 
Alternatively, work out 8 ÷ 12 = 2/3, so find 2/3 of each quantity.