ReasoningAges 7-9

Missing sequence terms

Use the constant step size between terms to find the missing middle number in a sequence. Review suitability for your learners before teaching.

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Worksheet StudioPractice pack · Ages 7-9

Take your time. Show your thinking.

12 questions · Seed 42 · Age guidance, not curriculum certification

View the answer key

Worksheet StudioAnswer key · Ages 7-9

Answers and reasoning. Review before teaching.

1. Find the missing number in the sequence: 15, 25, ____, 45, 55.
35
The sequence increases by 10 each step: 25 + 10 = 35.
2. Find the missing number in the sequence: 11, 20, ____, 38, 47.
29
The sequence increases by 9 each step: 20 + 9 = 29.
3. Find the missing number in the sequence: 1, 4, ____, 10, 13.
7
The sequence increases by 3 each step: 4 + 3 = 7.
4. Find the missing number in the sequence: 3, 12, ____, 30, 39.
21
The sequence increases by 9 each step: 12 + 9 = 21.
5. Find the missing number in the sequence: 11, 17, ____, 29, 35.
23
The sequence increases by 6 each step: 17 + 6 = 23.
6. Find the missing number in the sequence: 6, 14, ____, 30, 38.
22
The sequence increases by 8 each step: 14 + 8 = 22.
7. Find the missing number in the sequence: 2, 6, ____, 14, 18.
10
The sequence increases by 4 each step: 6 + 4 = 10.
8. Find the missing number in the sequence: 5, 11, ____, 23, 29.
17
The sequence increases by 6 each step: 11 + 6 = 17.
9. Find the missing number in the sequence: 14, 20, ____, 32, 38.
26
The sequence increases by 6 each step: 20 + 6 = 26.
10. Find the missing number in the sequence: 12, 16, ____, 24, 28.
20
The sequence increases by 4 each step: 16 + 4 = 20.
11. Find the missing number in the sequence: 4, 7, ____, 13, 16.
10
The sequence increases by 3 each step: 7 + 3 = 10.
12. Find the missing number in the sequence: 6, 12, ____, 24, 30.
18
The sequence increases by 6 each step: 12 + 6 = 18.

12 questions · Seed 42 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 7-9

Take your time. Show your thinking.

12 questions · Seed 42 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 7-9

Answers and reasoning. Review before teaching.

1. Find the missing number in the sequence: 15, 25, ____, 45, 55.
35
The sequence increases by 10 each step: 25 + 10 = 35.
2. Find the missing number in the sequence: 11, 20, ____, 38, 47.
29
The sequence increases by 9 each step: 20 + 9 = 29.
3. Find the missing number in the sequence: 1, 4, ____, 10, 13.
7
The sequence increases by 3 each step: 4 + 3 = 7.
4. Find the missing number in the sequence: 3, 12, ____, 30, 39.
21
The sequence increases by 9 each step: 12 + 9 = 21.
5. Find the missing number in the sequence: 11, 17, ____, 29, 35.
23
The sequence increases by 6 each step: 17 + 6 = 23.
6. Find the missing number in the sequence: 6, 14, ____, 30, 38.
22
The sequence increases by 8 each step: 14 + 8 = 22.
7. Find the missing number in the sequence: 2, 6, ____, 14, 18.
10
The sequence increases by 4 each step: 6 + 4 = 10.
8. Find the missing number in the sequence: 5, 11, ____, 23, 29.
17
The sequence increases by 6 each step: 11 + 6 = 17.
9. Find the missing number in the sequence: 14, 20, ____, 32, 38.
26
The sequence increases by 6 each step: 20 + 6 = 26.
10. Find the missing number in the sequence: 12, 16, ____, 24, 28.
20
The sequence increases by 4 each step: 16 + 4 = 20.
11. Find the missing number in the sequence: 4, 7, ____, 13, 16.
10
The sequence increases by 3 each step: 7 + 3 = 10.
12. Find the missing number in the sequence: 6, 12, ____, 24, 30.
18
The sequence increases by 6 each step: 12 + 6 = 18.

12 questions · Seed 42 · Age guidance, not curriculum certification