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 19 to make 20?
19 · 20 · Complements to 10, 20 & 100
2. How many more do you need to add to 4 to make 20?
4 · 20 · Complements to 10, 20 & 100
3. How many more do you need to add to 2 to make 12?
2 · 12 · Complements to 10, 20 & 100
4. How many more do you need to add to 11 to make 12?
11 · 12 · Complements to 10, 20 & 100
5. How many more do you need to add to 7 to make 12?
7 · 12 · Complements to 10, 20 & 100
6. How many more do you need to add to 6 to make 10?
6 · 10 · Complements to 10, 20 & 100
7. How many more do you need to add to 4 to make 12?
4 · 12 · Complements to 10, 20 & 100
8. How many more do you need to add to 15 to make 20?
15 · 20 · Complements to 10, 20 & 100
9. How many more do you need to add to 18 to make 20?
18 · 20 · Complements to 10, 20 & 100
10. How many more do you need to add to 6 to make 12?
6 · 12 · Complements to 10, 20 & 100
11. How many more do you need to add to 1 to make 10?
1 · 10 · Complements to 10, 20 & 100
12. How many more do you need to add to 8 to make 10?
8 · 10 · Complements to 10, 20 & 100

12 questions · Seed 104749 · 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 19 to make 20?
1
Subtract 19 from 20: 20 − 19 = 1.
2. How many more do you need to add to 4 to make 20?
16
Subtract 4 from 20: 20 − 4 = 16.
3. How many more do you need to add to 2 to make 12?
10
Subtract 2 from 12: 12 − 2 = 10.
4. How many more do you need to add to 11 to make 12?
1
Subtract 11 from 12: 12 − 11 = 1.
5. How many more do you need to add to 7 to make 12?
5
Subtract 7 from 12: 12 − 7 = 5.
6. How many more do you need to add to 6 to make 10?
4
Subtract 6 from 10: 10 − 6 = 4.
7. How many more do you need to add to 4 to make 12?
8
Subtract 4 from 12: 12 − 4 = 8.
8. How many more do you need to add to 15 to make 20?
5
Subtract 15 from 20: 20 − 15 = 5.
9. How many more do you need to add to 18 to make 20?
2
Subtract 18 from 20: 20 − 18 = 2.
10. How many more do you need to add to 6 to make 12?
6
Subtract 6 from 12: 12 − 6 = 6.
11. How many more do you need to add to 1 to make 10?
9
Subtract 1 from 10: 10 − 1 = 9.
12. How many more do you need to add to 8 to make 10?
2
Subtract 8 from 10: 10 − 8 = 2.

12 questions · Seed 104749 · 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 19 to make 20?
19 · 20 · Complements to 10, 20 & 100
2. How many more do you need to add to 4 to make 20?
4 · 20 · Complements to 10, 20 & 100
3. How many more do you need to add to 2 to make 12?
2 · 12 · Complements to 10, 20 & 100
4. How many more do you need to add to 11 to make 12?
11 · 12 · Complements to 10, 20 & 100
5. How many more do you need to add to 7 to make 12?
7 · 12 · Complements to 10, 20 & 100
6. How many more do you need to add to 6 to make 10?
6 · 10 · Complements to 10, 20 & 100
7. How many more do you need to add to 4 to make 12?
4 · 12 · Complements to 10, 20 & 100
8. How many more do you need to add to 15 to make 20?
15 · 20 · Complements to 10, 20 & 100
9. How many more do you need to add to 18 to make 20?
18 · 20 · Complements to 10, 20 & 100
10. How many more do you need to add to 6 to make 12?
6 · 12 · Complements to 10, 20 & 100
11. How many more do you need to add to 1 to make 10?
1 · 10 · Complements to 10, 20 & 100
12. How many more do you need to add to 8 to make 10?
8 · 10 · Complements to 10, 20 & 100

12 questions · Seed 104749 · 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 19 to make 20?
1
Subtract 19 from 20: 20 − 19 = 1.
2. How many more do you need to add to 4 to make 20?
16
Subtract 4 from 20: 20 − 4 = 16.
3. How many more do you need to add to 2 to make 12?
10
Subtract 2 from 12: 12 − 2 = 10.
4. How many more do you need to add to 11 to make 12?
1
Subtract 11 from 12: 12 − 11 = 1.
5. How many more do you need to add to 7 to make 12?
5
Subtract 7 from 12: 12 − 7 = 5.
6. How many more do you need to add to 6 to make 10?
4
Subtract 6 from 10: 10 − 6 = 4.
7. How many more do you need to add to 4 to make 12?
8
Subtract 4 from 12: 12 − 4 = 8.
8. How many more do you need to add to 15 to make 20?
5
Subtract 15 from 20: 20 − 15 = 5.
9. How many more do you need to add to 18 to make 20?
2
Subtract 18 from 20: 20 − 18 = 2.
10. How many more do you need to add to 6 to make 12?
6
Subtract 6 from 12: 12 − 6 = 6.
11. How many more do you need to add to 1 to make 10?
9
Subtract 1 from 10: 10 − 1 = 9.
12. How many more do you need to add to 8 to make 10?
2
Subtract 8 from 10: 10 − 8 = 2.

12 questions · Seed 104749 · Age guidance, not curriculum certification