### A good answer might be:

See below:

# Program Continued

Terms of the expression are pushed onto the stack as they are evaluated. Then the sum is initialized to -7 and the terms on the stack are popped and added to the sum.

    # Evaluate the expression ab - 12a + 18b - 7

            .globl  main
            lw      $t0,a          # get a
            lw      $t1,bb         # get b
            mul     $t0,$t0,$t1    # a*b
            subu    $sp,$sp,4      # push a*b onto stack
            sw      $t0,($sp)

            lw      $t0,a          # get a
            li      $t1,-12        #
            mul     $t0,$t0,$t1    # -12a
            subu    $sp,$sp,4      # push -12a onto stack
            sw      $t0,($sp)

            lw      $t0,bb         # get b
            li      $t1,18         #
            mul     $t0,$t0,$t1    # 18b
            subu    $sp,$sp,4      # push 18b onto stack
            sw      $t0,($sp)

            li      $t1,-7         # init sum to -7

            lw      $t0,_____      # pop 18b

            addu    $sp,$sp,______

            addu    $t1,$t1,$t0    # 18b -7

            . . . .

### QUESTION 7:

Fill in the blanks to pop the `18b` term.