Question

Use Euler's Formula to complete
Faces:23
Vertices:10
Edges:?

Answer 1

Know about the Euler's formula?

Answer 2

Eurler's formula basically says:

Faces + Vertices - Edges = 2

Answer 3

Plug and chug, and you're good to go.

Answer 4

It's kinda funny, the more general version of Euler's formula is simpler to remember because it looks like this:

(number of 0D stuff) - (number of 1D stuff) + (number of 2D stuff) - ... = X

X = 2 if the total number of stuff is odd (which it is for Euler's formula here), and X = 0 if the total number of stuff is even.

Since that's pretty vague, the + terms are the even dimensional stuff the 0D vertices and 2D faces while the - terms are the odd dimensional stuff, the 1D edges.