Teach you a simple method, absolutely correct, our teacher said.

4x4x2=32 (square centimeter)

If you don't understand, you can use another method.

4x4x6x2= 192 (square centimeter)

8x4x2+4x4x2+8x4x2= 160 (square centimeter)

192- 160=32 (square centimeter)

1 1.

( 1) 1

(2) 6

(3) 12

(4) 8

If you are satisfied, please adopt it. This is what the teacher told us, which is absolutely correct.