A Google search box will evaluate this according to the order of operations.
= 180÷9×(-12)÷6-20 . . . . evaluate parentheses first
= 20×(-12)÷6-20 . . . . . . . multiplication and division, left to right
= -240÷6-20 . . . . . . . . . . multiplication and division, left to right
= -40-20 . . . . . . . . . . . . . . multiplication and division, left to right
= -60 . . . . . . . . . . . . . . . . . addition and subtraction