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MathsAges 13-15

Percentage increase & decrease

Increase or decrease a starting value by a given percentage to find the new quantity. Review suitability for your learners before teaching.

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Age band:Ages 13-15 Ages 16-18

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Worksheet StudioPractice pack · Ages 13-15

Percentage increase & decrease

Take your time. Show your thinking.

1. Increase 80 by 30%.
80 · 30% · Percentage increase & decr…
2. Decrease 340 by 20%.
340 · 20% · Percentage increase & decr…
3. Increase 140 by 25%.
140 · 25% · Percentage increase & decr…
4. Decrease 400 by 20%.
400 · 20% · Percentage increase & decr…
5. Decrease 360 by 10%.
360 · 10% · Percentage increase & decr…
6. Decrease 240 by 40%.
240 · 40% · Percentage increase & decr…
7. Decrease 60 by 30%.
60 · 30% · Percentage increase & decr…
8. Increase 480 by 10%.
480 · 10% · Percentage increase & decr…
9. Increase 300 by 30%.
300 · 30% · Percentage increase & decr…
10. Decrease 280 by 50%.
280 · 50% · Percentage increase & decr…
11. Decrease 440 by 50%.
440 · 50% · Percentage increase & decr…
12. Decrease 260 by 25%.
260 · 25% · Percentage increase & decr…

12 questions · Seed 43 · Age guidance, not curriculum certification

View the answer key

Worksheet StudioAnswer key · Ages 13-15

Percentage increase & decrease

Answers and reasoning. Review before teaching.

1. Increase 80 by 30%.
104
30% of 80 is 24. 80 + 24 = 104.
2. Decrease 340 by 20%.
272
20% of 340 is 68. 340 − 68 = 272.
3. Increase 140 by 25%.
175
25% of 140 is 35. 140 + 35 = 175.
4. Decrease 400 by 20%.
320
20% of 400 is 80. 400 − 80 = 320.
5. Decrease 360 by 10%.
324
10% of 360 is 36. 360 − 36 = 324.
6. Decrease 240 by 40%.
144
40% of 240 is 96. 240 − 96 = 144.
7. Decrease 60 by 30%.
42
30% of 60 is 18. 60 − 18 = 42.
8. Increase 480 by 10%.
528
10% of 480 is 48. 480 + 48 = 528.
9. Increase 300 by 30%.
390
30% of 300 is 90. 300 + 90 = 390.
10. Decrease 280 by 50%.
140
50% of 280 is 140. 280 − 140 = 140.
11. Decrease 440 by 50%.
220
50% of 440 is 220. 440 − 220 = 220.
12. Decrease 260 by 25%.
195
25% of 260 is 65. 260 − 65 = 195.

12 questions · Seed 43 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 13-15

Percentage increase & decrease

Take your time. Show your thinking.

1. Increase 80 by 30%.
80 · 30% · Percentage increase & decr…
2. Decrease 340 by 20%.
340 · 20% · Percentage increase & decr…
3. Increase 140 by 25%.
140 · 25% · Percentage increase & decr…
4. Decrease 400 by 20%.
400 · 20% · Percentage increase & decr…
5. Decrease 360 by 10%.
360 · 10% · Percentage increase & decr…
6. Decrease 240 by 40%.
240 · 40% · Percentage increase & decr…
7. Decrease 60 by 30%.
60 · 30% · Percentage increase & decr…
8. Increase 480 by 10%.
480 · 10% · Percentage increase & decr…
9. Increase 300 by 30%.
300 · 30% · Percentage increase & decr…
10. Decrease 280 by 50%.
280 · 50% · Percentage increase & decr…
11. Decrease 440 by 50%.
440 · 50% · Percentage increase & decr…
12. Decrease 260 by 25%.
260 · 25% · Percentage increase & decr…

12 questions · Seed 43 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 13-15

Percentage increase & decrease

Answers and reasoning. Review before teaching.

1. Increase 80 by 30%.
104
30% of 80 is 24. 80 + 24 = 104.
2. Decrease 340 by 20%.
272
20% of 340 is 68. 340 − 68 = 272.
3. Increase 140 by 25%.
175
25% of 140 is 35. 140 + 35 = 175.
4. Decrease 400 by 20%.
320
20% of 400 is 80. 400 − 80 = 320.
5. Decrease 360 by 10%.
324
10% of 360 is 36. 360 − 36 = 324.
6. Decrease 240 by 40%.
144
40% of 240 is 96. 240 − 96 = 144.
7. Decrease 60 by 30%.
42
30% of 60 is 18. 60 − 18 = 42.
8. Increase 480 by 10%.
528
10% of 480 is 48. 480 + 48 = 528.
9. Increase 300 by 30%.
390
30% of 300 is 90. 300 + 90 = 390.
10. Decrease 280 by 50%.
140
50% of 280 is 140. 280 − 140 = 140.
11. Decrease 440 by 50%.
220
50% of 440 is 220. 440 − 220 = 220.
12. Decrease 260 by 25%.
195
25% of 260 is 65. 260 − 65 = 195.

12 questions · Seed 43 · Age guidance, not curriculum certification