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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 4-6
Missing sequence terms
Take your time. Show your thinking.
1. Find the missing number in the sequence: 15, 17, ____, 21, 23.
2. Find the missing number in the sequence: 5, 7, ____, 11, 13.
3. Find the missing number in the sequence: 15, 16, ____, 18, 19.
4. Find the missing number in the sequence: 17, 22, ____, 32, 37.
5. Find the missing number in the sequence: 16, 17, ____, 19, 20.
6. Find the missing number in the sequence: 19, 21, ____, 25, 27.
7. Find the missing number in the sequence: 11, 16, ____, 26, 31.
8. Find the missing number in the sequence: 5, 6, ____, 8, 9.
9. Find the missing number in the sequence: 1, 6, ____, 16, 21.
10. Find the missing number in the sequence: 3, 8, ____, 18, 23.
11. Find the missing number in the sequence: 12, 14, ____, 18, 20.
12. Find the missing number in the sequence: 6, 11, ____, 21, 26.
12 questions · Seed 68 · Age guidance, not curriculum certification
View the answer key
Worksheet StudioAnswer key · Ages 4-6
Missing sequence terms
Answers and reasoning. Review before teaching.
1. Find the missing number in the sequence: 15, 17, ____, 21, 23.
19The sequence increases by 2 each step: 17 + 2 = 19.
2. Find the missing number in the sequence: 5, 7, ____, 11, 13.
9The sequence increases by 2 each step: 7 + 2 = 9.
3. Find the missing number in the sequence: 15, 16, ____, 18, 19.
17The sequence increases by 1 each step: 16 + 1 = 17.
4. Find the missing number in the sequence: 17, 22, ____, 32, 37.
27The sequence increases by 5 each step: 22 + 5 = 27.
5. Find the missing number in the sequence: 16, 17, ____, 19, 20.
18The sequence increases by 1 each step: 17 + 1 = 18.
6. Find the missing number in the sequence: 19, 21, ____, 25, 27.
23The sequence increases by 2 each step: 21 + 2 = 23.
7. Find the missing number in the sequence: 11, 16, ____, 26, 31.
21The sequence increases by 5 each step: 16 + 5 = 21.
8. Find the missing number in the sequence: 5, 6, ____, 8, 9.
7The sequence increases by 1 each step: 6 + 1 = 7.
9. Find the missing number in the sequence: 1, 6, ____, 16, 21.
11The sequence increases by 5 each step: 6 + 5 = 11.
10. Find the missing number in the sequence: 3, 8, ____, 18, 23.
13The sequence increases by 5 each step: 8 + 5 = 13.
11. Find the missing number in the sequence: 12, 14, ____, 18, 20.
16The sequence increases by 2 each step: 14 + 2 = 16.
12. Find the missing number in the sequence: 6, 11, ____, 21, 26.
16The sequence increases by 5 each step: 11 + 5 = 16.
12 questions · Seed 68 · Age guidance, not curriculum certification
Worksheet StudioPractice pack · Ages 4-6
Missing sequence terms
Take your time. Show your thinking.
1. Find the missing number in the sequence: 15, 17, ____, 21, 23.
2. Find the missing number in the sequence: 5, 7, ____, 11, 13.
3. Find the missing number in the sequence: 15, 16, ____, 18, 19.
4. Find the missing number in the sequence: 17, 22, ____, 32, 37.
5. Find the missing number in the sequence: 16, 17, ____, 19, 20.
6. Find the missing number in the sequence: 19, 21, ____, 25, 27.
7. Find the missing number in the sequence: 11, 16, ____, 26, 31.
8. Find the missing number in the sequence: 5, 6, ____, 8, 9.
9. Find the missing number in the sequence: 1, 6, ____, 16, 21.
10. Find the missing number in the sequence: 3, 8, ____, 18, 23.
11. Find the missing number in the sequence: 12, 14, ____, 18, 20.
12. Find the missing number in the sequence: 6, 11, ____, 21, 26.
12 questions · Seed 68 · Age guidance, not curriculum certification
Worksheet StudioAnswer key · Ages 4-6
Missing sequence terms
Answers and reasoning. Review before teaching.
1. Find the missing number in the sequence: 15, 17, ____, 21, 23.
19The sequence increases by 2 each step: 17 + 2 = 19.
2. Find the missing number in the sequence: 5, 7, ____, 11, 13.
9The sequence increases by 2 each step: 7 + 2 = 9.
3. Find the missing number in the sequence: 15, 16, ____, 18, 19.
17The sequence increases by 1 each step: 16 + 1 = 17.
4. Find the missing number in the sequence: 17, 22, ____, 32, 37.
27The sequence increases by 5 each step: 22 + 5 = 27.
5. Find the missing number in the sequence: 16, 17, ____, 19, 20.
18The sequence increases by 1 each step: 17 + 1 = 18.
6. Find the missing number in the sequence: 19, 21, ____, 25, 27.
23The sequence increases by 2 each step: 21 + 2 = 23.
7. Find the missing number in the sequence: 11, 16, ____, 26, 31.
21The sequence increases by 5 each step: 16 + 5 = 21.
8. Find the missing number in the sequence: 5, 6, ____, 8, 9.
7The sequence increases by 1 each step: 6 + 1 = 7.
9. Find the missing number in the sequence: 1, 6, ____, 16, 21.
11The sequence increases by 5 each step: 6 + 5 = 11.
10. Find the missing number in the sequence: 3, 8, ____, 18, 23.
13The sequence increases by 5 each step: 8 + 5 = 13.
11. Find the missing number in the sequence: 12, 14, ____, 18, 20.
16The sequence increases by 2 each step: 14 + 2 = 16.
12. Find the missing number in the sequence: 6, 11, ____, 21, 26.
16The sequence increases by 5 each step: 11 + 5 = 16.
12 questions · Seed 68 · Age guidance, not curriculum certification