@coolboymew@cinerion@hidden I just said that to clarify that you're gluing the shapes together along the triangle surfaces, not doing something weird like gluing a triangle onto a square.
You basically did what the SAT test writers did (which contains a mistake).
But there's also a language issue: a "square pyramid" looks like the pic, I think you interpreted it as a "cube". So you'd do 3 + 4 = 7.