Okay, in the problem I am doing there is no amount of edges. That is what I am supposed to solve for.

The formula is:
V - E + F = 2

So am I supposed to add or subtract the E? I don't know and this confuses me...

How many edges does a convex polyhedron have if it has 16 vertices and 18 faces?

So if I need to solve for edges:

16-E+18=2

I don't even know if this is right!!!