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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: 9, 13, ____, 21, 25.
2. Find the missing number in the sequence: 18, 27, ____, 45, 54.
3. Find the missing number in the sequence: 14, 23, ____, 41, 50.
4. Find the missing number in the sequence: 10, 14, ____, 22, 26.
5. Find the missing number in the sequence: 7, 13, ____, 25, 31.
6. Find the missing number in the sequence: 19, 29, ____, 49, 59.
7. Find the missing number in the sequence: 18, 22, ____, 30, 34.
8. Find the missing number in the sequence: 11, 18, ____, 32, 39.
9. Find the missing number in the sequence: 7, 14, ____, 28, 35.
10. Find the missing number in the sequence: 7, 16, ____, 34, 43.
11. Find the missing number in the sequence: 19, 25, ____, 37, 43.
12. Find the missing number in the sequence: 18, 21, ____, 27, 30.
12 questions · Seed 85 · 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: 9, 13, ____, 21, 25.
17The sequence increases by 4 each step: 13 + 4 = 17.
2. Find the missing number in the sequence: 18, 27, ____, 45, 54.
36The sequence increases by 9 each step: 27 + 9 = 36.
3. Find the missing number in the sequence: 14, 23, ____, 41, 50.
32The sequence increases by 9 each step: 23 + 9 = 32.
4. Find the missing number in the sequence: 10, 14, ____, 22, 26.
18The sequence increases by 4 each step: 14 + 4 = 18.
5. Find the missing number in the sequence: 7, 13, ____, 25, 31.
19The sequence increases by 6 each step: 13 + 6 = 19.
6. Find the missing number in the sequence: 19, 29, ____, 49, 59.
39The sequence increases by 10 each step: 29 + 10 = 39.
7. Find the missing number in the sequence: 18, 22, ____, 30, 34.
26The sequence increases by 4 each step: 22 + 4 = 26.
8. Find the missing number in the sequence: 11, 18, ____, 32, 39.
25The sequence increases by 7 each step: 18 + 7 = 25.
9. Find the missing number in the sequence: 7, 14, ____, 28, 35.
21The sequence increases by 7 each step: 14 + 7 = 21.
10. Find the missing number in the sequence: 7, 16, ____, 34, 43.
25The sequence increases by 9 each step: 16 + 9 = 25.
11. Find the missing number in the sequence: 19, 25, ____, 37, 43.
31The sequence increases by 6 each step: 25 + 6 = 31.
12. Find the missing number in the sequence: 18, 21, ____, 27, 30.
24The sequence increases by 3 each step: 21 + 3 = 24.
12 questions · Seed 85 · 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: 9, 13, ____, 21, 25.
2. Find the missing number in the sequence: 18, 27, ____, 45, 54.
3. Find the missing number in the sequence: 14, 23, ____, 41, 50.
4. Find the missing number in the sequence: 10, 14, ____, 22, 26.
5. Find the missing number in the sequence: 7, 13, ____, 25, 31.
6. Find the missing number in the sequence: 19, 29, ____, 49, 59.
7. Find the missing number in the sequence: 18, 22, ____, 30, 34.
8. Find the missing number in the sequence: 11, 18, ____, 32, 39.
9. Find the missing number in the sequence: 7, 14, ____, 28, 35.
10. Find the missing number in the sequence: 7, 16, ____, 34, 43.
11. Find the missing number in the sequence: 19, 25, ____, 37, 43.
12. Find the missing number in the sequence: 18, 21, ____, 27, 30.
12 questions · Seed 85 · 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: 9, 13, ____, 21, 25.
17The sequence increases by 4 each step: 13 + 4 = 17.
2. Find the missing number in the sequence: 18, 27, ____, 45, 54.
36The sequence increases by 9 each step: 27 + 9 = 36.
3. Find the missing number in the sequence: 14, 23, ____, 41, 50.
32The sequence increases by 9 each step: 23 + 9 = 32.
4. Find the missing number in the sequence: 10, 14, ____, 22, 26.
18The sequence increases by 4 each step: 14 + 4 = 18.
5. Find the missing number in the sequence: 7, 13, ____, 25, 31.
19The sequence increases by 6 each step: 13 + 6 = 19.
6. Find the missing number in the sequence: 19, 29, ____, 49, 59.
39The sequence increases by 10 each step: 29 + 10 = 39.
7. Find the missing number in the sequence: 18, 22, ____, 30, 34.
26The sequence increases by 4 each step: 22 + 4 = 26.
8. Find the missing number in the sequence: 11, 18, ____, 32, 39.
25The sequence increases by 7 each step: 18 + 7 = 25.
9. Find the missing number in the sequence: 7, 14, ____, 28, 35.
21The sequence increases by 7 each step: 14 + 7 = 21.
10. Find the missing number in the sequence: 7, 16, ____, 34, 43.
25The sequence increases by 9 each step: 16 + 9 = 25.
11. Find the missing number in the sequence: 19, 25, ____, 37, 43.
31The sequence increases by 6 each step: 25 + 6 = 31.
12. Find the missing number in the sequence: 18, 21, ____, 27, 30.
24The sequence increases by 3 each step: 21 + 3 = 24.
12 questions · Seed 85 · Age guidance, not curriculum certification