There are two boxes that are "easy" to complete: the first and last boxes of the bottom row. Do you agree?

One place to begin is at the top of the pyramid.

So,

To get 235, add 58 and C and 55 and C. The number C is used twice to get 235, once as part of A and once as part of B. Can you find C?

In a similar way, find the missing numbers in these sections of the Pyramid.