Mixing Colours 2

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Purpose

These exercises and activities are for students to use independently of the teacher to practice number properties

Achievement Objectives
Specific Learning Outcomes
  • Solve ratio problems.
  • Explain why the process of finding equivalent ratios is important when we compare ratios (question 3, exercise 1).
Description of Mathematics

Proportions and Ratios, AP (Stage 8)

Required Resource Materials
  • Exercises with answers (PDF or Word)
Activity

Prior knowledge

  • Explain what a ratio is, and how it relates to a fraction
  • Understand the importance of comparing like to like in mathematics

Background

This is a brief  activity to support the mixing paint activity. The answers give a brief explanation of why the ratios need to be made equivalent before a comparison is made.

Note that students may come up with other ways of working out which mix gives the stronger colour, for example, 4:5 or 7:11 could be compared as fractions. The first has 4/9 or 44% blue, while the second has 7/18 or 39% blue – but this is getting tricky without a calculator (hint one third is 33.3%, so one eighteenth is about 5.5%).

Comments on the Exercises

Exercise 1
Asks students to show ratios on a number line and then determine the ratio with the highest red component.

Exercise 2
Asks students to determine from pairs of ratios which pair has the most blue, and then question 2 asks which pair has the more orange.

 

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Level Five