Okay so let's break this down into TWO shapes :
A being the top shape and B being the bottom one.
【☆】★【☆】★【☆】★【☆】★【☆】
Volume of A
5 * 2 * 2 - 20 (using the formula length * width * height)
Volume of B
4 * 6 * 2 = 48 (using the formula l*w*h)
Add both of these volumes together to get the volume of the total shape : 68cm cubed (I don't know how to add units on this keyboard)
【☆】★【☆】★【☆】★【☆】★【☆】【☆】★【☆】★【☆】★【☆】
