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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.
Worksheet StudioPractice pack · Ages 7-9
Missing sequence terms
Take your time. Show your thinking.
1. Find the missing number in the sequence: 3, 6, ____, 12, 15.
2. Find the missing number in the sequence: 7, 11, ____, 19, 23.
3. Find the missing number in the sequence: 18, 25, ____, 39, 46.
4. Find the missing number in the sequence: 17, 26, ____, 44, 53.
5. Find the missing number in the sequence: 4, 7, ____, 13, 16.
6. Find the missing number in the sequence: 20, 29, ____, 47, 56.
7. Find the missing number in the sequence: 16, 23, ____, 37, 44.
8. Find the missing number in the sequence: 10, 17, ____, 31, 38.
9. Find the missing number in the sequence: 8, 17, ____, 35, 44.
10. Find the missing number in the sequence: 5, 11, ____, 23, 29.
11. Find the missing number in the sequence: 12, 22, ____, 42, 52.
12. Find the missing number in the sequence: 15, 24, ____, 42, 51.
12 questions · Seed 72 · Age guidance, not curriculum certification
View the answer key
Worksheet StudioAnswer key · Ages 7-9
Missing sequence terms
Answers and reasoning. Review before teaching.
1. Find the missing number in the sequence: 3, 6, ____, 12, 15.
9The sequence increases by 3 each step: 6 + 3 = 9.
2. Find the missing number in the sequence: 7, 11, ____, 19, 23.
15The sequence increases by 4 each step: 11 + 4 = 15.
3. Find the missing number in the sequence: 18, 25, ____, 39, 46.
32The sequence increases by 7 each step: 25 + 7 = 32.
4. Find the missing number in the sequence: 17, 26, ____, 44, 53.
35The sequence increases by 9 each step: 26 + 9 = 35.
5. Find the missing number in the sequence: 4, 7, ____, 13, 16.
10The sequence increases by 3 each step: 7 + 3 = 10.
6. Find the missing number in the sequence: 20, 29, ____, 47, 56.
38The sequence increases by 9 each step: 29 + 9 = 38.
7. Find the missing number in the sequence: 16, 23, ____, 37, 44.
30The sequence increases by 7 each step: 23 + 7 = 30.
8. Find the missing number in the sequence: 10, 17, ____, 31, 38.
24The sequence increases by 7 each step: 17 + 7 = 24.
9. Find the missing number in the sequence: 8, 17, ____, 35, 44.
26The sequence increases by 9 each step: 17 + 9 = 26.
10. Find the missing number in the sequence: 5, 11, ____, 23, 29.
17The sequence increases by 6 each step: 11 + 6 = 17.
11. Find the missing number in the sequence: 12, 22, ____, 42, 52.
32The sequence increases by 10 each step: 22 + 10 = 32.
12. Find the missing number in the sequence: 15, 24, ____, 42, 51.
33The sequence increases by 9 each step: 24 + 9 = 33.
12 questions · Seed 72 · Age guidance, not curriculum certification
Worksheet StudioPractice pack · Ages 7-9
Missing sequence terms
Take your time. Show your thinking.
1. Find the missing number in the sequence: 3, 6, ____, 12, 15.
2. Find the missing number in the sequence: 7, 11, ____, 19, 23.
3. Find the missing number in the sequence: 18, 25, ____, 39, 46.
4. Find the missing number in the sequence: 17, 26, ____, 44, 53.
5. Find the missing number in the sequence: 4, 7, ____, 13, 16.
6. Find the missing number in the sequence: 20, 29, ____, 47, 56.
7. Find the missing number in the sequence: 16, 23, ____, 37, 44.
8. Find the missing number in the sequence: 10, 17, ____, 31, 38.
9. Find the missing number in the sequence: 8, 17, ____, 35, 44.
10. Find the missing number in the sequence: 5, 11, ____, 23, 29.
11. Find the missing number in the sequence: 12, 22, ____, 42, 52.
12. Find the missing number in the sequence: 15, 24, ____, 42, 51.
12 questions · Seed 72 · Age guidance, not curriculum certification
Worksheet StudioAnswer key · Ages 7-9
Missing sequence terms
Answers and reasoning. Review before teaching.
1. Find the missing number in the sequence: 3, 6, ____, 12, 15.
9The sequence increases by 3 each step: 6 + 3 = 9.
2. Find the missing number in the sequence: 7, 11, ____, 19, 23.
15The sequence increases by 4 each step: 11 + 4 = 15.
3. Find the missing number in the sequence: 18, 25, ____, 39, 46.
32The sequence increases by 7 each step: 25 + 7 = 32.
4. Find the missing number in the sequence: 17, 26, ____, 44, 53.
35The sequence increases by 9 each step: 26 + 9 = 35.
5. Find the missing number in the sequence: 4, 7, ____, 13, 16.
10The sequence increases by 3 each step: 7 + 3 = 10.
6. Find the missing number in the sequence: 20, 29, ____, 47, 56.
38The sequence increases by 9 each step: 29 + 9 = 38.
7. Find the missing number in the sequence: 16, 23, ____, 37, 44.
30The sequence increases by 7 each step: 23 + 7 = 30.
8. Find the missing number in the sequence: 10, 17, ____, 31, 38.
24The sequence increases by 7 each step: 17 + 7 = 24.
9. Find the missing number in the sequence: 8, 17, ____, 35, 44.
26The sequence increases by 9 each step: 17 + 9 = 26.
10. Find the missing number in the sequence: 5, 11, ____, 23, 29.
17The sequence increases by 6 each step: 11 + 6 = 17.
11. Find the missing number in the sequence: 12, 22, ____, 42, 52.
32The sequence increases by 10 each step: 22 + 10 = 32.
12. Find the missing number in the sequence: 15, 24, ____, 42, 51.
33The sequence increases by 9 each step: 24 + 9 = 33.
12 questions · Seed 72 · Age guidance, not curriculum certification