Pros and Cons

'Pros and Cons' printed from https://nrich.maths.org/

If $p$ is a positive integer and $q$ is a negative integer, which of the following is the greatest?

$p-q$ $q-p$ $p+q$ $-p-q$

This problem is taken from the UKMT Mathematical Challenges.

You can find more short problems, arranged by curriculum topic, in our short problems collection.