Parentheses indicate that their contents are to be calculated first before applying anything outside them. So -3^3 means raise 3 to power 3 first (power has priority) then apply minus=-27. (-3)^3 means raise -3 to power 3, so raise -1 to power 3=-1 and multiply by 3^3 giving -1*27=-27. So the answers are the same for different reasons.