Answer: The other way around
Explanation:
Our task is to answer the question:
Is -15 greater than -5, or is it the other way around?
To answer that, we will imagine a number line:
<-----------------------|-------------------------------|------------------------------------------------>
-15 -5
Basically, the number that's closer to the left is smaller; the number that's closer to the right is larger. -15 is closer to the left than -5, so it's smaller than -15.
-5, on the other hand, is closer to the right, and, therefore, it's greater than -15.