ArreniteRatios, rates and percentages
Read together
A ratio compares two amounts. If a recipe uses 2 cups of rice to 3 cups of water, the ratio is 2 to 3, written 2:3. Equivalent ratios scale up or down: 4:6 is the same as 2:3.
A rate compares different units, such as 60 kilometres in 2 hours. The unit rate is the amount for one: 30 kilometres per hour.
A percentage is a ratio out of 100. 25% means 25 out of 100, or 1/4. To find 25% of 80, you can calculate 80 × 0.25 = 20.
Do it
- Scale a recipe: if a recipe for 4 uses 3 cups of rice, how much for 10 people? Write the ratio and solve.
- Compare two shops: one sells 6 pens for 9, another 10 pens for 14. Find the price for one pen in each. Which is cheaper?
- Find 15% of the price of something you want, as if it were a discount. What is the new price? Check your answer.
- Find a percentage in the news or on a product label and explain what it means.
Talk about it
- How do you check that two ratios are equal?
- Why is the unit rate useful for comparing?
For the grown-up
Ratios, rates and percentages are used in cooking, shopping, health and finance. Encourage your teen to estimate before calculating, and to notice when numbers in ads are misleading.
Where this comes from
This is a play and practice activity with no factual claims to source.
Written with AI assistance and checked against the sources listed. Please read it before sharing it with a child.