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Grade 8 · Math · Unit 2 of 11

Ratios, Rates & Proportions

Unit rates, best buys and scale

What your child practises

Simplifying ratios, finding missing terms in equivalent ratios, comparing unit prices, working with speed, scaling recipes and map distances, and turning a part of a whole into a percent.

Nunavut Curriculum approved guide: Alberta Mathematics K–9 (2007), Number · ratios, rates and proportional reasoning

How we explain it

Children can open this short lesson before they practise.

  1. A ratio compares two amounts, like 2 : 3.
  2. A rate compares different units, like dollars per pen.
  3. A unit rate is the amount for 1: divide to find it.

Example: 6 pens cost $4.50. What is the price for 1 pen? Divide the cost by the number of pens. 4.50 ÷ 6 = 0.75. Answer: $0.75 per pen

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    A bag has 20 red marbles and 12 blue marbles. What is the ratio of red to blue in lowest terms?

    • 5:8
    • 5:3
    • 3:5
    • 20:12
    • 6:4

  2. Question 2

    7 : 8 = 35 : ?

    answer box

  3. Question 3

    4 notebooks cost $3.40. What is the price of one notebook, in dollars?

    answer box

  4. Question 4

    A cyclist rides 320 km in 5 hours at a steady pace. What is the speed in km per hour?

    answer boxkm/h

  5. Question 5

    Pack A: 4 juice boxes for $0.80. Pack B: 12 juice boxes for $2.64. Which pack is the better buy?

    • Pack A
    • They cost the same per box
    • Pack B

  6. Question 6

    A recipe for 6 people uses 6 cups of rice. How many cups are needed for 30 people?

    answer boxcups

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