MathsAges 10-12

Decimal addition

Add numbers in tenths. Keep the decimal places aligned as you calculate. Review suitability for your learners before teaching.

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Worksheet StudioPractice pack · Ages 10-12

Take your time. Show your thinking.

12 questions · Seed 47 · Age guidance, not curriculum certification

View the answer key

Worksheet StudioAnswer key · Ages 10-12

Answers and reasoning. Review before teaching.

1. 12.7 + 17.0 = ____
29.7
Add 127 tenths and 170 tenths to get 297 tenths.
2. 9.0 + 14.6 = ____
23.6
Add 90 tenths and 146 tenths to get 236 tenths.
3. 4.0 + 8.5 = ____
12.5
Add 40 tenths and 85 tenths to get 125 tenths.
4. 10.1 + 5.7 = ____
15.8
Add 101 tenths and 57 tenths to get 158 tenths.
5. 15.4 + 1.2 = ____
16.6
Add 154 tenths and 12 tenths to get 166 tenths.
6. 12.9 + 16.5 = ____
29.4
Add 129 tenths and 165 tenths to get 294 tenths.
7. 5.5 + 9.5 = ____
15.0
Add 55 tenths and 95 tenths to get 150 tenths.
8. 6.4 + 7.0 = ____
13.4
Add 64 tenths and 70 tenths to get 134 tenths.
9. 19.6 + 19.3 = ____
38.9
Add 196 tenths and 193 tenths to get 389 tenths.
10. 1.1 + 1.9 = ____
3.0
Add 11 tenths and 19 tenths to get 30 tenths.
11. 2.9 + 7.9 = ____
10.8
Add 29 tenths and 79 tenths to get 108 tenths.
12. 10.1 + 17.0 = ____
27.1
Add 101 tenths and 170 tenths to get 271 tenths.

12 questions · Seed 47 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 10-12

Take your time. Show your thinking.

12 questions · Seed 47 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 10-12

Answers and reasoning. Review before teaching.

1. 12.7 + 17.0 = ____
29.7
Add 127 tenths and 170 tenths to get 297 tenths.
2. 9.0 + 14.6 = ____
23.6
Add 90 tenths and 146 tenths to get 236 tenths.
3. 4.0 + 8.5 = ____
12.5
Add 40 tenths and 85 tenths to get 125 tenths.
4. 10.1 + 5.7 = ____
15.8
Add 101 tenths and 57 tenths to get 158 tenths.
5. 15.4 + 1.2 = ____
16.6
Add 154 tenths and 12 tenths to get 166 tenths.
6. 12.9 + 16.5 = ____
29.4
Add 129 tenths and 165 tenths to get 294 tenths.
7. 5.5 + 9.5 = ____
15.0
Add 55 tenths and 95 tenths to get 150 tenths.
8. 6.4 + 7.0 = ____
13.4
Add 64 tenths and 70 tenths to get 134 tenths.
9. 19.6 + 19.3 = ____
38.9
Add 196 tenths and 193 tenths to get 389 tenths.
10. 1.1 + 1.9 = ____
3.0
Add 11 tenths and 19 tenths to get 30 tenths.
11. 2.9 + 7.9 = ____
10.8
Add 29 tenths and 79 tenths to get 108 tenths.
12. 10.1 + 17.0 = ____
27.1
Add 101 tenths and 170 tenths to get 271 tenths.

12 questions · Seed 47 · Age guidance, not curriculum certification