MathsAges 4-6

Complements to 10, 20 & 100

Find how many more are needed to complete a benchmark number such as 10, 20, 50 or 100. Review suitability for your learners before teaching.

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Worksheet StudioPractice pack · Ages 4-6

Take your time. Show your thinking.

1. How many more do you need to add to 8 to make 20?
8 · 20 · Complements to 10, 20 & 100
2. How many more do you need to add to 12 to make 15?
12 · 15 · Complements to 10, 20 & 100
3. How many more do you need to add to 1 to make 10?
1 · 10 · Complements to 10, 20 & 100
4. How many more do you need to add to 3 to make 10?
3 · 10 · Complements to 10, 20 & 100
5. How many more do you need to add to 10 to make 15?
10 · 15 · Complements to 10, 20 & 100
6. How many more do you need to add to 11 to make 12?
11 · 12 · Complements to 10, 20 & 100
7. How many more do you need to add to 5 to make 10?
5 · 10 · Complements to 10, 20 & 100
8. How many more do you need to add to 4 to make 20?
4 · 20 · Complements to 10, 20 & 100
9. How many more do you need to add to 9 to make 10?
9 · 10 · Complements to 10, 20 & 100
10. How many more do you need to add to 13 to make 15?
13 · 15 · Complements to 10, 20 & 100
11. How many more do you need to add to 8 to make 10?
8 · 10 · Complements to 10, 20 & 100
12. How many more do you need to add to 6 to make 10?
6 · 10 · Complements to 10, 20 & 100

12 questions · Seed 104768 · Age guidance, not curriculum certification

View the answer key

Worksheet StudioAnswer key · Ages 4-6

Answers and reasoning. Review before teaching.

1. How many more do you need to add to 8 to make 20?
12
Subtract 8 from 20: 20 − 8 = 12.
2. How many more do you need to add to 12 to make 15?
3
Subtract 12 from 15: 15 − 12 = 3.
3. How many more do you need to add to 1 to make 10?
9
Subtract 1 from 10: 10 − 1 = 9.
4. How many more do you need to add to 3 to make 10?
7
Subtract 3 from 10: 10 − 3 = 7.
5. How many more do you need to add to 10 to make 15?
5
Subtract 10 from 15: 15 − 10 = 5.
6. How many more do you need to add to 11 to make 12?
1
Subtract 11 from 12: 12 − 11 = 1.
7. How many more do you need to add to 5 to make 10?
5
Subtract 5 from 10: 10 − 5 = 5.
8. How many more do you need to add to 4 to make 20?
16
Subtract 4 from 20: 20 − 4 = 16.
9. How many more do you need to add to 9 to make 10?
1
Subtract 9 from 10: 10 − 9 = 1.
10. How many more do you need to add to 13 to make 15?
2
Subtract 13 from 15: 15 − 13 = 2.
11. How many more do you need to add to 8 to make 10?
2
Subtract 8 from 10: 10 − 8 = 2.
12. How many more do you need to add to 6 to make 10?
4
Subtract 6 from 10: 10 − 6 = 4.

12 questions · Seed 104768 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 4-6

Take your time. Show your thinking.

1. How many more do you need to add to 8 to make 20?
8 · 20 · Complements to 10, 20 & 100
2. How many more do you need to add to 12 to make 15?
12 · 15 · Complements to 10, 20 & 100
3. How many more do you need to add to 1 to make 10?
1 · 10 · Complements to 10, 20 & 100
4. How many more do you need to add to 3 to make 10?
3 · 10 · Complements to 10, 20 & 100
5. How many more do you need to add to 10 to make 15?
10 · 15 · Complements to 10, 20 & 100
6. How many more do you need to add to 11 to make 12?
11 · 12 · Complements to 10, 20 & 100
7. How many more do you need to add to 5 to make 10?
5 · 10 · Complements to 10, 20 & 100
8. How many more do you need to add to 4 to make 20?
4 · 20 · Complements to 10, 20 & 100
9. How many more do you need to add to 9 to make 10?
9 · 10 · Complements to 10, 20 & 100
10. How many more do you need to add to 13 to make 15?
13 · 15 · Complements to 10, 20 & 100
11. How many more do you need to add to 8 to make 10?
8 · 10 · Complements to 10, 20 & 100
12. How many more do you need to add to 6 to make 10?
6 · 10 · Complements to 10, 20 & 100

12 questions · Seed 104768 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 4-6

Answers and reasoning. Review before teaching.

1. How many more do you need to add to 8 to make 20?
12
Subtract 8 from 20: 20 − 8 = 12.
2. How many more do you need to add to 12 to make 15?
3
Subtract 12 from 15: 15 − 12 = 3.
3. How many more do you need to add to 1 to make 10?
9
Subtract 1 from 10: 10 − 1 = 9.
4. How many more do you need to add to 3 to make 10?
7
Subtract 3 from 10: 10 − 3 = 7.
5. How many more do you need to add to 10 to make 15?
5
Subtract 10 from 15: 15 − 10 = 5.
6. How many more do you need to add to 11 to make 12?
1
Subtract 11 from 12: 12 − 11 = 1.
7. How many more do you need to add to 5 to make 10?
5
Subtract 5 from 10: 10 − 5 = 5.
8. How many more do you need to add to 4 to make 20?
16
Subtract 4 from 20: 20 − 4 = 16.
9. How many more do you need to add to 9 to make 10?
1
Subtract 9 from 10: 10 − 9 = 1.
10. How many more do you need to add to 13 to make 15?
2
Subtract 13 from 15: 15 − 13 = 2.
11. How many more do you need to add to 8 to make 10?
2
Subtract 8 from 10: 10 − 8 = 2.
12. How many more do you need to add to 6 to make 10?
4
Subtract 6 from 10: 10 − 6 = 4.

12 questions · Seed 104768 · Age guidance, not curriculum certification