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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: 3, 8, ____, 18, 23.
2. Find the missing number in the sequence: 20, 25, ____, 35, 40.
3. Find the missing number in the sequence: 13, 18, ____, 28, 33.
4. Find the missing number in the sequence: 19, 21, ____, 25, 27.
5. Find the missing number in the sequence: 15, 20, ____, 30, 35.
6. Find the missing number in the sequence: 5, 7, ____, 11, 13.
7. Find the missing number in the sequence: 15, 17, ____, 21, 23.
8. Find the missing number in the sequence: 8, 13, ____, 23, 28.
9. Find the missing number in the sequence: 12, 13, ____, 15, 16.
10. Find the missing number in the sequence: 7, 12, ____, 22, 27.
11. Find the missing number in the sequence: 15, 16, ____, 18, 19.
12. Find the missing number in the sequence: 9, 10, ____, 12, 13.
12 questions · Seed 65 · 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: 3, 8, ____, 18, 23.
13The sequence increases by 5 each step: 8 + 5 = 13.
2. Find the missing number in the sequence: 20, 25, ____, 35, 40.
30The sequence increases by 5 each step: 25 + 5 = 30.
3. Find the missing number in the sequence: 13, 18, ____, 28, 33.
23The sequence increases by 5 each step: 18 + 5 = 23.
4. Find the missing number in the sequence: 19, 21, ____, 25, 27.
23The sequence increases by 2 each step: 21 + 2 = 23.
5. Find the missing number in the sequence: 15, 20, ____, 30, 35.
25The sequence increases by 5 each step: 20 + 5 = 25.
6. Find the missing number in the sequence: 5, 7, ____, 11, 13.
9The sequence increases by 2 each step: 7 + 2 = 9.
7. Find the missing number in the sequence: 15, 17, ____, 21, 23.
19The sequence increases by 2 each step: 17 + 2 = 19.
8. Find the missing number in the sequence: 8, 13, ____, 23, 28.
18The sequence increases by 5 each step: 13 + 5 = 18.
9. Find the missing number in the sequence: 12, 13, ____, 15, 16.
14The sequence increases by 1 each step: 13 + 1 = 14.
10. Find the missing number in the sequence: 7, 12, ____, 22, 27.
17The sequence increases by 5 each step: 12 + 5 = 17.
11. Find the missing number in the sequence: 15, 16, ____, 18, 19.
17The sequence increases by 1 each step: 16 + 1 = 17.
12. Find the missing number in the sequence: 9, 10, ____, 12, 13.
11The sequence increases by 1 each step: 10 + 1 = 11.
12 questions · Seed 65 · 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: 3, 8, ____, 18, 23.
2. Find the missing number in the sequence: 20, 25, ____, 35, 40.
3. Find the missing number in the sequence: 13, 18, ____, 28, 33.
4. Find the missing number in the sequence: 19, 21, ____, 25, 27.
5. Find the missing number in the sequence: 15, 20, ____, 30, 35.
6. Find the missing number in the sequence: 5, 7, ____, 11, 13.
7. Find the missing number in the sequence: 15, 17, ____, 21, 23.
8. Find the missing number in the sequence: 8, 13, ____, 23, 28.
9. Find the missing number in the sequence: 12, 13, ____, 15, 16.
10. Find the missing number in the sequence: 7, 12, ____, 22, 27.
11. Find the missing number in the sequence: 15, 16, ____, 18, 19.
12. Find the missing number in the sequence: 9, 10, ____, 12, 13.
12 questions · Seed 65 · 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: 3, 8, ____, 18, 23.
13The sequence increases by 5 each step: 8 + 5 = 13.
2. Find the missing number in the sequence: 20, 25, ____, 35, 40.
30The sequence increases by 5 each step: 25 + 5 = 30.
3. Find the missing number in the sequence: 13, 18, ____, 28, 33.
23The sequence increases by 5 each step: 18 + 5 = 23.
4. Find the missing number in the sequence: 19, 21, ____, 25, 27.
23The sequence increases by 2 each step: 21 + 2 = 23.
5. Find the missing number in the sequence: 15, 20, ____, 30, 35.
25The sequence increases by 5 each step: 20 + 5 = 25.
6. Find the missing number in the sequence: 5, 7, ____, 11, 13.
9The sequence increases by 2 each step: 7 + 2 = 9.
7. Find the missing number in the sequence: 15, 17, ____, 21, 23.
19The sequence increases by 2 each step: 17 + 2 = 19.
8. Find the missing number in the sequence: 8, 13, ____, 23, 28.
18The sequence increases by 5 each step: 13 + 5 = 18.
9. Find the missing number in the sequence: 12, 13, ____, 15, 16.
14The sequence increases by 1 each step: 13 + 1 = 14.
10. Find the missing number in the sequence: 7, 12, ____, 22, 27.
17The sequence increases by 5 each step: 12 + 5 = 17.
11. Find the missing number in the sequence: 15, 16, ____, 18, 19.
17The sequence increases by 1 each step: 16 + 1 = 17.
12. Find the missing number in the sequence: 9, 10, ____, 12, 13.
11The sequence increases by 1 each step: 10 + 1 = 11.
12 questions · Seed 65 · Age guidance, not curriculum certification