Find the next number in the series.
88, 108, 130, 154, ________

Let's find the difference between consecutive numbers in the series:
* $108-88=20$
* $130-108=22$
* $154-130=24$

The differences are increasing by $+2$ at each step ($20,22,24$).
Therefore, the next difference must be $24+2=26$.

$$\text{Next number}=154+26=180$$