Number sequences
Find the next number in an increasing or decreasing sequence.
Practice + answer key · 2 pages
Worksheet settings12 questions · 2 columns · A4
Paper size
Algebra
What you’ll practice
Find the next term of an arithmetic sequence.
Look for the same difference between each pair of neighboring terms. Check it in more than one place, then use it to find the next number.
How this skill works
Subtract the first term from the second to find a possible difference.
Check that difference against the next pairs, then add it to the final visible term.
Worked example
Find the next term: 12, 9, 6, 3, __.
- 9 − 12 = −3.
- Every step subtracts 3.
- 3 − 3 = 0.
Answer: 0
Teaching notes
- Check more than one step before deciding on a rule.
Practice questions
- Write the next term: −3, −2, −1, 0, __.
- Write the next term: 18, 9, 0, −9, __.
- Write the next term: 20, 24, 28, 32, __.
- Write the next term: −9, −11, −13, −15, __.
- Write the next term: 16, 11, 6, 1, __.
- Write the next term: 0, 4, 8, 12, __.
- Write the next term: −7, −15, −23, −31, __.
- Write the next term: 11, 6, 1, −4, __.
- Write the next term: −9, −10, −11, −12, __.
- Write the next term: 15, 12, 9, 6, __.
- Write the next term: −7, −3, 1, 5, __.
- Write the next term: 17, 15, 13, 11, __.
Answers and steps
- 1
- Each step adds 1.
- 0 + (1) = 1.
- −18
- Each step adds −9.
- −9 + (−9) = −18.
- 36
- Each step adds 4.
- 32 + (4) = 36.
- −17
- Each step adds −2.
- −15 + (−2) = −17.
- −4
- Each step adds −5.
- 1 + (−5) = −4.
- 16
- Each step adds 4.
- 12 + (4) = 16.
- −39
- Each step adds −8.
- −31 + (−8) = −39.
- −9
- Each step adds −5.
- −4 + (−5) = −9.
- −13
- Each step adds −1.
- −12 + (−1) = −13.
- 3
- Each step adds −3.
- 6 + (−3) = 3.
- 9
- Each step adds 4.
- 5 + (4) = 9.
- 9
- Each step adds −2.
- 11 + (−2) = 9.