Grade 6 · Math · Unit 7 of 18
Percents & Ratios
Mental percents, ratios and rates
What your child practises
Finding 1%, 5%, 10%, 15%, 25% and 50% of a number in your head, and solving ratio, rate and percent problems.
Prince Edward Island Curriculum curriculum outcome: N5; N6 · ratios, rates, and finding common percents of an amount
How we explain it
Children can open this short lesson before they practise.
- Percent means out of 100.
- Use 10% (divide by 10) and 1% (divide by 100) to build other percents.
- A ratio compares amounts. A rate compares different units, like km per hour.
Example: What is 30% of 50? 10% of 50 = 5. 30% is three of those: 3 × 5 = 15. Answer: 15
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
What is 5% of 160?
answer box
8
Hint: Find 10%, then halve it.
Question 2
What is 15% of 100?
answer box
15
Hint: Find 10% and 5%, then add them.
Question 3
A game costs $80. It is 25% off. What is the sale price in dollars?
answer box
60
Hint: Find 25% of the price, then take it away.
Question 4
A cyclist rides 28 km in 4 hours. At the same rate, how far does the cyclist ride in 6 hours?
answer box
42
Hint: First find the rate: 28 ÷ 4 = 7 km per hour.
Question 5
In a class, the ratio of girls to boys is 3 to 4. There are 49 students. How many are girls?
Girls Boys Total 3 4 7 ? 49 answer box
21
Hint: There are 7 parts. Each part is 49 ÷ 7 = 7 students.
Question 6
Jay got 2 out of 4 questions right. What percent is that?
answer box%
50 %
Hint: Write 2/4 as a fraction out of 100.