Step 7 Objective

Divide a quantity into two or more parts in a given ratio; use the unitary method to solve simple word problems involving ratio and direct proportion.

Examples of what pupils should know and be able to do

Solve problems such as:

Probing questions

If the ratio of boys to girls in a class is 3 : 1, could there be exactly 30 children in the class?
Why?

Could there be 25 boys?
Why?


5 miles is about the same as 8 km. Can you make up some conversion questions that you could answer mentally?

Can you make up some conversion questions for which you would have to use a more formal method?

How would you work out the answers to these questions?

What if pupils find this a barrier?

Use ratio strips ITP - Zip file (458Kb) to provide a visual image to support the understanding of ratio, e.g. to divide £44 in the ratio 1 : 3


diagram showing one block numbered eleven pounds next to three stacked blocks, each numbered eleven pounds


See phase 3 of the unit plan in the Year 8 multiplicative relationships mini pack - Acrobat pdf document (203Kb) which is focused on problem solving.