Grade 9 · Math · Unit 15 of 15
Money Decisions
Value, interest and budgets
What your child practises
Items that gain or lose value over time, simple and compound interest, how rate, time and down payments change the cost of borrowing, adjusting a budget, and adding 13% HST.
Ontario Curriculum expectation: F1.1, F1.2, F1.3, F1.4 · appreciation and depreciation, borrowing costs, interest and changing a budget
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
A $1000 item loses 10% of its value each year. What is it worth after 2 years, in dollars?
answer box
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810
Hint: Year 1: 1000 × 0.9 = 900. Year 2: multiply by 0.9 again to get 810.
Question 2
A painting bought for $500 gains $100 in value each year. What is it worth after 3 years, in dollars?
answer box
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800
Hint: Gain: 100 × 3 = 300. Add to the start: 500 + 300 = 800.
Question 3
Rent rises by $150, and the entertainment budget is cut by $100. Income stays the same and everything else is unchanged. How much is left for savings now, in dollars?
Monthly budget Item Dollars Income 2300 Rent 900 Food 250 Entertainment 250 Savings 900 answer box
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850
Hint: Savings is what remains of income. The change: 900 − 150 + 100 = 850.
Question 4
What does this table of values show?
Value over time Year Value 0 $900 1 $1050 2 $1200 3 $1350 - Appreciation: the value is growing
- Depreciation: the value is shrinking
- Neither: the value stays the same
Show answer
Appreciation: the value is growing
Hint: Appreciation means the value goes up over time; depreciation means it goes down.
Question 5
On a graph, a car's value falls from $20 000 at year 0 to $17 000 at year 2. How many dollars does it lose per year on average?
answer box
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1500
Hint: Change in value ÷ change in time = 3000 ÷ 2 = 1500.
Question 6
You borrow $5000 for 2 years at 10% per year. Which way of charging interest costs more, and by how much?
- Compound interest, by $50.00
- Simple interest, by $50.00
- Compound interest, by $100.00
- They cost the same
Show answer
Compound interest, by $50.00
Hint: Simple interest is $1000 (the same each year). Compound interest also charges interest on last year's interest, so it costs $50.00 more over 2 years.