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 12 to make 15?
12 · 15 · Complements to 10, 20 & 100
2. How many more do you need to add to 15 to make 20?
15 · 20 · Complements to 10, 20 & 100
3. How many more do you need to add to 19 to make 20?
19 · 20 · Complements to 10, 20 & 100
4. How many more do you need to add to 9 to make 10?
9 · 10 · Complements to 10, 20 & 100
5. How many more do you need to add to 2 to make 20?
2 · 20 · Complements to 10, 20 & 100
6. How many more do you need to add to 4 to make 15?
4 · 15 · Complements to 10, 20 & 100
7. How many more do you need to add to 18 to make 20?
18 · 20 · Complements to 10, 20 & 100
8. How many more do you need to add to 3 to make 10?
3 · 10 · Complements to 10, 20 & 100
9. How many more do you need to add to 6 to make 10?
6 · 10 · Complements to 10, 20 & 100
10. How many more do you need to add to 7 to make 10?
7 · 10 · Complements to 10, 20 & 100
11. How many more do you need to add to 7 to make 15?
7 · 15 · Complements to 10, 20 & 100
12. How many more do you need to add to 11 to make 12?
11 · 12 · Complements to 10, 20 & 100

12 questions · Seed 104772 · 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 12 to make 15?
3
Subtract 12 from 15: 15 − 12 = 3.
2. How many more do you need to add to 15 to make 20?
5
Subtract 15 from 20: 20 − 15 = 5.
3. How many more do you need to add to 19 to make 20?
1
Subtract 19 from 20: 20 − 19 = 1.
4. How many more do you need to add to 9 to make 10?
1
Subtract 9 from 10: 10 − 9 = 1.
5. How many more do you need to add to 2 to make 20?
18
Subtract 2 from 20: 20 − 2 = 18.
6. How many more do you need to add to 4 to make 15?
11
Subtract 4 from 15: 15 − 4 = 11.
7. How many more do you need to add to 18 to make 20?
2
Subtract 18 from 20: 20 − 18 = 2.
8. How many more do you need to add to 3 to make 10?
7
Subtract 3 from 10: 10 − 3 = 7.
9. How many more do you need to add to 6 to make 10?
4
Subtract 6 from 10: 10 − 6 = 4.
10. How many more do you need to add to 7 to make 10?
3
Subtract 7 from 10: 10 − 7 = 3.
11. How many more do you need to add to 7 to make 15?
8
Subtract 7 from 15: 15 − 7 = 8.
12. How many more do you need to add to 11 to make 12?
1
Subtract 11 from 12: 12 − 11 = 1.

12 questions · Seed 104772 · 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 12 to make 15?
12 · 15 · Complements to 10, 20 & 100
2. How many more do you need to add to 15 to make 20?
15 · 20 · Complements to 10, 20 & 100
3. How many more do you need to add to 19 to make 20?
19 · 20 · Complements to 10, 20 & 100
4. How many more do you need to add to 9 to make 10?
9 · 10 · Complements to 10, 20 & 100
5. How many more do you need to add to 2 to make 20?
2 · 20 · Complements to 10, 20 & 100
6. How many more do you need to add to 4 to make 15?
4 · 15 · Complements to 10, 20 & 100
7. How many more do you need to add to 18 to make 20?
18 · 20 · Complements to 10, 20 & 100
8. How many more do you need to add to 3 to make 10?
3 · 10 · Complements to 10, 20 & 100
9. How many more do you need to add to 6 to make 10?
6 · 10 · Complements to 10, 20 & 100
10. How many more do you need to add to 7 to make 10?
7 · 10 · Complements to 10, 20 & 100
11. How many more do you need to add to 7 to make 15?
7 · 15 · Complements to 10, 20 & 100
12. How many more do you need to add to 11 to make 12?
11 · 12 · Complements to 10, 20 & 100

12 questions · Seed 104772 · 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 12 to make 15?
3
Subtract 12 from 15: 15 − 12 = 3.
2. How many more do you need to add to 15 to make 20?
5
Subtract 15 from 20: 20 − 15 = 5.
3. How many more do you need to add to 19 to make 20?
1
Subtract 19 from 20: 20 − 19 = 1.
4. How many more do you need to add to 9 to make 10?
1
Subtract 9 from 10: 10 − 9 = 1.
5. How many more do you need to add to 2 to make 20?
18
Subtract 2 from 20: 20 − 2 = 18.
6. How many more do you need to add to 4 to make 15?
11
Subtract 4 from 15: 15 − 4 = 11.
7. How many more do you need to add to 18 to make 20?
2
Subtract 18 from 20: 20 − 18 = 2.
8. How many more do you need to add to 3 to make 10?
7
Subtract 3 from 10: 10 − 3 = 7.
9. How many more do you need to add to 6 to make 10?
4
Subtract 6 from 10: 10 − 6 = 4.
10. How many more do you need to add to 7 to make 10?
3
Subtract 7 from 10: 10 − 7 = 3.
11. How many more do you need to add to 7 to make 15?
8
Subtract 7 from 15: 15 − 7 = 8.
12. How many more do you need to add to 11 to make 12?
1
Subtract 11 from 12: 12 − 11 = 1.

12 questions · Seed 104772 · Age guidance, not curriculum certification