2 slices are left left because if you change the 8 to a fraction it will turn to this 8/8 and you need to change 3/4 to have the same denominator as the 8/8 so 3/4 will turn to 6/8 and then you subtract 8/8 by 6/8 and itll be 2/8 left so the answwer is 2 slices left