The master method allows us to solve certain recurrences of the form
$$T(n) = aT(n/b)+f(n)\,,$$
where $a\ge1$ and $b>1$ are constants and $f(n)$ is a positive function with some further restrictions that aren't important for this question.
The above recurrence describes the running time of an algorithm that divides a problem of size $n$ into $a$ subproblems, each of size $n/b$. This is intuitive in the case that $a=b$ (for example, merge sort divides the list into two parts of size $n/2$) but are there any examples of recursive algorithms that follow this schema but where $a\neq b$?