The second one seems about right.
If that is -2+1+4+13 I think it should be 16
3,075ft^3 (cubic feet)
(the ^3 means to the power of 3. aka cubed)
4[(8+4)10] + 24
so 8 + 4 is 12. Multiply that by 10 and that's 120.
120 + 24 is 144
144 × 4 is 576
for "devided by 2^3" do you mean divided by 2/3?
If so then its 576 ÷ 2/3 = 96