MathsAges 10-12

Decimal addition

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

Choose “Save as PDF” to keep a copy. Use your browser’s paper setting for A4 or Letter.

Worksheet StudioPractice pack · Ages 10-12

Take your time. Show your thinking.

12 questions · Seed 50 · Age guidance, not curriculum certification

View the answer key

Worksheet StudioAnswer key · Ages 10-12

Answers and reasoning. Review before teaching.

1. 3.3 + 12.6 = ____
15.9
Add 33 tenths and 126 tenths to get 159 tenths.
2. 18.8 + 5.8 = ____
24.6
Add 188 tenths and 58 tenths to get 246 tenths.
3. 12.6 + 3.5 = ____
16.1
Add 126 tenths and 35 tenths to get 161 tenths.
4. 4.4 + 10.9 = ____
15.3
Add 44 tenths and 109 tenths to get 153 tenths.
5. 18.0 + 15.7 = ____
33.7
Add 180 tenths and 157 tenths to get 337 tenths.
6. 19.6 + 4.3 = ____
23.9
Add 196 tenths and 43 tenths to get 239 tenths.
7. 5.4 + 7.6 = ____
13.0
Add 54 tenths and 76 tenths to get 130 tenths.
8. 5.7 + 16.7 = ____
22.4
Add 57 tenths and 167 tenths to get 224 tenths.
9. 15.9 + 4.3 = ____
20.2
Add 159 tenths and 43 tenths to get 202 tenths.
10. 1.9 + 3.3 = ____
5.2
Add 19 tenths and 33 tenths to get 52 tenths.
11. 13.0 + 8.5 = ____
21.5
Add 130 tenths and 85 tenths to get 215 tenths.
12. 10.1 + 4.9 = ____
15.0
Add 101 tenths and 49 tenths to get 150 tenths.

12 questions · Seed 50 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 10-12

Take your time. Show your thinking.

12 questions · Seed 50 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 10-12

Answers and reasoning. Review before teaching.

1. 3.3 + 12.6 = ____
15.9
Add 33 tenths and 126 tenths to get 159 tenths.
2. 18.8 + 5.8 = ____
24.6
Add 188 tenths and 58 tenths to get 246 tenths.
3. 12.6 + 3.5 = ____
16.1
Add 126 tenths and 35 tenths to get 161 tenths.
4. 4.4 + 10.9 = ____
15.3
Add 44 tenths and 109 tenths to get 153 tenths.
5. 18.0 + 15.7 = ____
33.7
Add 180 tenths and 157 tenths to get 337 tenths.
6. 19.6 + 4.3 = ____
23.9
Add 196 tenths and 43 tenths to get 239 tenths.
7. 5.4 + 7.6 = ____
13.0
Add 54 tenths and 76 tenths to get 130 tenths.
8. 5.7 + 16.7 = ____
22.4
Add 57 tenths and 167 tenths to get 224 tenths.
9. 15.9 + 4.3 = ____
20.2
Add 159 tenths and 43 tenths to get 202 tenths.
10. 1.9 + 3.3 = ____
5.2
Add 19 tenths and 33 tenths to get 52 tenths.
11. 13.0 + 8.5 = ____
21.5
Add 130 tenths and 85 tenths to get 215 tenths.
12. 10.1 + 4.9 = ____
15.0
Add 101 tenths and 49 tenths to get 150 tenths.

12 questions · Seed 50 · Age guidance, not curriculum certification