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.


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?