Representing shared portions (Ratio and Percentage.) Strand: Numbers (Lesson 2)

 FOCUS QUESTION

How can I represent shared portions?

SPECIFIC OBJS.

1.       Solve problems which require the uses of equivalent ratios.

2.       Use ratio to compare quantities.

CONTENT SUMMARY

ENGAGE

Students will review past lesson on ratio by taking turns in solving simple problems orally.

EXPLORE

Read  the problem below and tell what information you have been provided with, and how you could go about solving the problem.

  Father gave his two boys , Kevin and Adrian the sum of $600 to be shared between themselves  in the ratio 2:3. How much money will each boy get.

Identify the amount to be shared

How  should it be shared and which share represents the share for each boy?

(They will observe as teacher demonstrates how the problem could be solved.)

Total number of parts = 2 + 3 = 5 

Kevin’s share will be 2/5 x 600= $240

Adrian’s share will be 3/5 x 600 = $360

Now decide if there is another way to find Adrian’s share other that the example shown.

Discuss among yourselves in your groups how the amount of money received by Adrian could be calculated.

Method 2

Let's look at another way in which we could solve problems of this type.

Now use each of the methods to solve the problems.

EXPLAIN

Explain the rules of solving the problem above. Use your work boards to correctly solve  the following similar problem, then report in your groups how you arrived at the answers.

Share 30 plums between Helen and Sue in the ratio 5:10.

EXTEND/ELABORATE

Solve problems of the type below in their groups and individually.

How many marbles will each person get if 60 marbles are shared in the ratio 1:2:3?

EVALUATE

Question 1 

N.B. Pay attention to the different units of measurement in part 3 of the exercise below.

Question 2 

(A) Amy and Taylor shared $1000 in the ratio 3:7. Calculate each child's share.

(B) How many apples would each student get if 200 of them are shared among Connor, Jordana and               Clayonique in the ratio 1:4:5?

(C) 200 stamps were shared among Sue, Dave and Lorean in the ratio 1:9:10. Calculate the largest         share.