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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: 5, 9, ____, 17, 21.
2. Find the missing number in the sequence: 17, 26, ____, 44, 53.
3. Find the missing number in the sequence: 7, 10, ____, 16, 19.
4. Find the missing number in the sequence: 20, 23, ____, 29, 32.
5. Find the missing number in the sequence: 4, 12, ____, 28, 36.
6. Find the missing number in the sequence: 11, 18, ____, 32, 39.
7. Find the missing number in the sequence: 19, 29, ____, 49, 59.
8. Find the missing number in the sequence: 17, 25, ____, 41, 49.
9. Find the missing number in the sequence: 4, 13, ____, 31, 40.
10. Find the missing number in the sequence: 1, 8, ____, 22, 29.
11. Find the missing number in the sequence: 1, 10, ____, 28, 37.
12. Find the missing number in the sequence: 11, 17, ____, 29, 35.
12 questions · Seed 75 · 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: 5, 9, ____, 17, 21.
13The sequence increases by 4 each step: 9 + 4 = 13.
2. Find the missing number in the sequence: 17, 26, ____, 44, 53.
35The sequence increases by 9 each step: 26 + 9 = 35.
3. Find the missing number in the sequence: 7, 10, ____, 16, 19.
13The sequence increases by 3 each step: 10 + 3 = 13.
4. Find the missing number in the sequence: 20, 23, ____, 29, 32.
26The sequence increases by 3 each step: 23 + 3 = 26.
5. Find the missing number in the sequence: 4, 12, ____, 28, 36.
20The sequence increases by 8 each step: 12 + 8 = 20.
6. Find the missing number in the sequence: 11, 18, ____, 32, 39.
25The sequence increases by 7 each step: 18 + 7 = 25.
7. Find the missing number in the sequence: 19, 29, ____, 49, 59.
39The sequence increases by 10 each step: 29 + 10 = 39.
8. Find the missing number in the sequence: 17, 25, ____, 41, 49.
33The sequence increases by 8 each step: 25 + 8 = 33.
9. Find the missing number in the sequence: 4, 13, ____, 31, 40.
22The sequence increases by 9 each step: 13 + 9 = 22.
10. Find the missing number in the sequence: 1, 8, ____, 22, 29.
15The sequence increases by 7 each step: 8 + 7 = 15.
11. Find the missing number in the sequence: 1, 10, ____, 28, 37.
19The sequence increases by 9 each step: 10 + 9 = 19.
12. Find the missing number in the sequence: 11, 17, ____, 29, 35.
23The sequence increases by 6 each step: 17 + 6 = 23.
12 questions · Seed 75 · 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: 5, 9, ____, 17, 21.
2. Find the missing number in the sequence: 17, 26, ____, 44, 53.
3. Find the missing number in the sequence: 7, 10, ____, 16, 19.
4. Find the missing number in the sequence: 20, 23, ____, 29, 32.
5. Find the missing number in the sequence: 4, 12, ____, 28, 36.
6. Find the missing number in the sequence: 11, 18, ____, 32, 39.
7. Find the missing number in the sequence: 19, 29, ____, 49, 59.
8. Find the missing number in the sequence: 17, 25, ____, 41, 49.
9. Find the missing number in the sequence: 4, 13, ____, 31, 40.
10. Find the missing number in the sequence: 1, 8, ____, 22, 29.
11. Find the missing number in the sequence: 1, 10, ____, 28, 37.
12. Find the missing number in the sequence: 11, 17, ____, 29, 35.
12 questions · Seed 75 · 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: 5, 9, ____, 17, 21.
13The sequence increases by 4 each step: 9 + 4 = 13.
2. Find the missing number in the sequence: 17, 26, ____, 44, 53.
35The sequence increases by 9 each step: 26 + 9 = 35.
3. Find the missing number in the sequence: 7, 10, ____, 16, 19.
13The sequence increases by 3 each step: 10 + 3 = 13.
4. Find the missing number in the sequence: 20, 23, ____, 29, 32.
26The sequence increases by 3 each step: 23 + 3 = 26.
5. Find the missing number in the sequence: 4, 12, ____, 28, 36.
20The sequence increases by 8 each step: 12 + 8 = 20.
6. Find the missing number in the sequence: 11, 18, ____, 32, 39.
25The sequence increases by 7 each step: 18 + 7 = 25.
7. Find the missing number in the sequence: 19, 29, ____, 49, 59.
39The sequence increases by 10 each step: 29 + 10 = 39.
8. Find the missing number in the sequence: 17, 25, ____, 41, 49.
33The sequence increases by 8 each step: 25 + 8 = 33.
9. Find the missing number in the sequence: 4, 13, ____, 31, 40.
22The sequence increases by 9 each step: 13 + 9 = 22.
10. Find the missing number in the sequence: 1, 8, ____, 22, 29.
15The sequence increases by 7 each step: 8 + 7 = 15.
11. Find the missing number in the sequence: 1, 10, ____, 28, 37.
19The sequence increases by 9 each step: 10 + 9 = 19.
12. Find the missing number in the sequence: 11, 17, ____, 29, 35.
23The sequence increases by 6 each step: 17 + 6 = 23.
12 questions · Seed 75 · Age guidance, not curriculum certification