Question 6: 30/2= 15

Question 7: Can you cut 18?

Question 8: A: Because a circle can surround all faces, but a square can't.

Question10: 24/4 = 66x5/12 = 5/26x4/12 = 26x3/12 = 3/25/2x2/3 = 7.5.

Question 13: (6/2)X(6/2)x(6/2)

Question14:10x10x10x3/3.14x (20/2x20/2)

Question 15: 3.14x1x15 = 47.1.47.1x1.2.

Question 16: Surface area: 20x20x5+3.14x10x/kloc-0+3.14x10x2x20/2 Volume: 20x20x20+3.

Question 19 is drawing. You drew it yourself. I can't draw it for you. I typed them one by one.