Seed packets

Achievement objectives

NA5-4: Use rates and ratios.

Description of mathematics

• Proportions and ratios, AP (stage 8).

Required materials

See Materials that come with this resource to download:

• Seed packets homework activity (.doc)
• Seed packets homework activity (.pdf)
• Seed packets class activity (.doc)
• Seed packets class activity (.pdf)

Activity

Prior knowledge

• Add 2 digit numbers or multiply by a 2 digit number (stage 7).
• Double 2 digit numbers.

Background

In using these data tables, there are 2 ways of generating the sets of numbers required either working horizontally or vertically. With the numbers provided in the table, working horizontally does not invoke skip counting, but can be solved easily using a multiplicative strategy. Be wary of introducing this as students may rapidly move beyond their knowledge of basic facts if this is introduced. (For example, in question 2 students are using a ratio of 1:4, and have to work out 4 lots of 24.) However, discuss with students how to construct the answers using a mixture of strategies. For example, by working vertically on questions 1 and 2 students could construct their answers using addition strategies and/or doubling. (For example, 4 × 24 is double 24 = 48 and double 48 = 96.) Alternatively, when working horizontally, the answer for 4, when doubled will give the answer for 8.

Comments on the exercises

Exercise 1

This exercise asks students to complete ratio tables and use the tables to answer questions.

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