Year 9 Percentage Increase and Decrease Worksheet — Level 1 — Practice Set 3 — Answers
Answer sheet with worked solutions for the Year 9 percentages worksheet.
Success TutoringWorksheetsAnswer sheetYear 9 · Mathematics · PercentagesYear 9 Percentage Increase and Decrease Worksheet — Level 1 — Practice Set 3 — Answers
Percentage change = change ÷ original amount × 100. Always divide by the original amount.
1.A price changes from $350 to $280. Find the percentage decrease.
Answer: 20%
- Change = 350 − 280 = 70
- 70 ÷ 350 × 100 = 20%
2.A price changes from $300 to $330. Find the percentage increase.
Answer: 10%
- Change = 330 − 300 = 30
- 30 ÷ 300 × 100 = 10%
3.A price changes from $120 to $144. Find the percentage increase.
Answer: 20%
- Change = 144 − 120 = 24
- 24 ÷ 120 × 100 = 20%
4.A price changes from $310 to $465. Find the percentage increase.
Answer: 50%
- Change = 465 − 310 = 155
- 155 ÷ 310 × 100 = 50%
5.A price changes from $270 to $405. Find the percentage increase.
Answer: 50%
- Change = 405 − 270 = 135
- 135 ÷ 270 × 100 = 50%
6.A price changes from $360 to $324. Find the percentage decrease.
Answer: 10%
- Change = 360 − 324 = 36
- 36 ÷ 360 × 100 = 10%
7.A price changes from $110 to $88. Find the percentage decrease.
Answer: 20%
- Change = 110 − 88 = 22
- 22 ÷ 110 × 100 = 20%
8.A price changes from $350 to $315. Find the percentage decrease.
Answer: 10%
- Change = 350 − 315 = 35
- 35 ÷ 350 × 100 = 10%
9.A price changes from $170 to $204. Find the percentage increase.
Answer: 20%
- Change = 204 − 170 = 34
- 34 ÷ 170 × 100 = 20%
10.A price changes from $300 to $270. Find the percentage decrease.
Answer: 10%
- Change = 300 − 270 = 30
- 30 ÷ 300 × 100 = 10%
Marking tips
- Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
- For open-ended tasks, use the success criteria as a checklist rather than looking for one "right" answer.
- Celebrate what went well first, then pick one thing to work on next.