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 106 · 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: 3, 6, ____, 12, 15.
9
The sequence increases by 3 each step: 6 + 3 = 9.
2. Find the missing number in the sequence: 13, 23, ____, 43, 53.
33
The sequence increases by 10 each step: 23 + 10 = 33.
3. Find the missing number in the sequence: 7, 13, ____, 25, 31.
19
The sequence increases by 6 each step: 13 + 6 = 19.
4. Find the missing number in the sequence: 11, 18, ____, 32, 39.
25
The sequence increases by 7 each step: 18 + 7 = 25.
5. Find the missing number in the sequence: 6, 15, ____, 33, 42.
24
The sequence increases by 9 each step: 15 + 9 = 24.
6. Find the missing number in the sequence: 5, 11, ____, 23, 29.
17
The sequence increases by 6 each step: 11 + 6 = 17.
7. Find the missing number in the sequence: 3, 9, ____, 21, 27.
15
The sequence increases by 6 each step: 9 + 6 = 15.
8. Find the missing number in the sequence: 3, 12, ____, 30, 39.
21
The sequence increases by 9 each step: 12 + 9 = 21.
9. Find the missing number in the sequence: 7, 16, ____, 34, 43.
25
The sequence increases by 9 each step: 16 + 9 = 25.
10. Find the missing number in the sequence: 1, 5, ____, 13, 17.
9
The sequence increases by 4 each step: 5 + 4 = 9.
11. Find the missing number in the sequence: 20, 27, ____, 41, 48.
34
The sequence increases by 7 each step: 27 + 7 = 34.
12. Find the missing number in the sequence: 15, 22, ____, 36, 43.
29
The sequence increases by 7 each step: 22 + 7 = 29.

12 questions · Seed 106 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 7-9

Take your time. Show your thinking.

12 questions · Seed 106 · 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: 3, 6, ____, 12, 15.
9
The sequence increases by 3 each step: 6 + 3 = 9.
2. Find the missing number in the sequence: 13, 23, ____, 43, 53.
33
The sequence increases by 10 each step: 23 + 10 = 33.
3. Find the missing number in the sequence: 7, 13, ____, 25, 31.
19
The sequence increases by 6 each step: 13 + 6 = 19.
4. Find the missing number in the sequence: 11, 18, ____, 32, 39.
25
The sequence increases by 7 each step: 18 + 7 = 25.
5. Find the missing number in the sequence: 6, 15, ____, 33, 42.
24
The sequence increases by 9 each step: 15 + 9 = 24.
6. Find the missing number in the sequence: 5, 11, ____, 23, 29.
17
The sequence increases by 6 each step: 11 + 6 = 17.
7. Find the missing number in the sequence: 3, 9, ____, 21, 27.
15
The sequence increases by 6 each step: 9 + 6 = 15.
8. Find the missing number in the sequence: 3, 12, ____, 30, 39.
21
The sequence increases by 9 each step: 12 + 9 = 21.
9. Find the missing number in the sequence: 7, 16, ____, 34, 43.
25
The sequence increases by 9 each step: 16 + 9 = 25.
10. Find the missing number in the sequence: 1, 5, ____, 13, 17.
9
The sequence increases by 4 each step: 5 + 4 = 9.
11. Find the missing number in the sequence: 20, 27, ____, 41, 48.
34
The sequence increases by 7 each step: 27 + 7 = 34.
12. Find the missing number in the sequence: 15, 22, ____, 36, 43.
29
The sequence increases by 7 each step: 22 + 7 = 29.

12 questions · Seed 106 · Age guidance, not curriculum certification