Free practice · numeric · easy
Practice
Extend an arithmetic sequence
What number comes next: 7, 11, 15, 19, ...?
Constant-difference test
The +4 rule survives every shown transition
Proposed ruleAdd 4 to the previous term
- 7→+4→11Fits
- 11→+4→15Fits
- 15→+4→19Fits
ConclusionOne more application gives 19 + 4 = 23.
A reliable extension uses one precise rule and checks every adjacent pair before producing the next term.