How many edges in one cube?

Answer 1

If the corners of the top-most face are labelled A, B, C and D then there are four edges, AB, BC, CD and DA. If the corners of the bottom-most face are labelled E, F G and H, then there are four edges, EF, FG, GH and HE. The edges joining the top-most face to the bottom-most face are AE, BF, CG and DH. Making a total of 12 edges.