Answer
$\{1, 2, 5, 10, 25, 50, 125, 250\}$
Work Step by Step
To list the factors of a number, we list all of the whole numbers that we can multiply to get the number. In the case of the number $250$, the factors are $\{1, 2, 5, 10, 25, 50, 125, 250\}$.
