Question

so i am working on a finance project for school and it told me from the wheel of life i got a 1500$ raise at my job which my monthly take home pay is: $ 2,787 before the raise, and after the tax reductions { tax rate is 12%} now my question is do i add that 1500 before or after the tax rdcutions ~side note i added it before the tax reduction just making sure i did this right before i turned it in~