Let $I$ be an ideal of a commutative ring $R$ with a reduction $J=$ $\left(a_1, \ldots, a_n\right), I^{r+1}=J I^r$. If $r \geq n$ show that $\left(a_1^r, \ldots, a_n^r\right)$ is a reduction of $I^r$ and the reduction number is at most $n$. (A treatment, with additional references, of the reduction numbers of powers of ideals can be found in [Hoa93].)