You'll probably get asked to compare the accuracy of different types of sums. Here are the main things you need to remember.
There are some things you need to know that we didn't include in the list. For example, if the function is increasing, is the LHS an over- or under-estimate? You should be able to figure that out
in about ten seconds by drawing this picture:
The rectangle doesn't cover enough area, so the LHS gives an underestimate. That means the RHS must be an overestimate.