Number sequences
On this page children practise recognising the step rule in a sequence of three-digit numbers and filling in missing terms. Start with the short method and the examples, then use the online practice or print a worksheet with answers.
How to solve this
- Find the rule of a sequence by subtracting any term from the next: the difference is the step size.
- Steps can be larger (50s, 100s) or involve alternating patterns — verify the rule with at least two gaps.
- Check by applying the rule to every gap in the sequence: each must match exactly.
Examples
100, 200, 300, __, __
400, 500
250, 275, 300, __
325
Practice problems with answers
Solve these problems on paper or out loud, then check the answer key. The online practice and the printable worksheet give a new set every time.
- 400, 401, 402, 403, ___
- 500, 502, 504, 506, ___
- 0, 2, 4, 6, ___
- 100, 110, 120, 130, ___
- 250, 300, 350, 400, ___
- 300, 301, 302, 303, ___
- 50, 75, 100, 125, ___
- 300, 310, 320, 330, ___
Show answers
- 404
- 508
- 8
- 140
- 450
- 304
- 150
- 340