it helps you with recipes by adding and subtracting the amount from the package...say you need to leave 4 cups of sugar in the bag and you have 6 cups in the bag so you need to subtract 4 from 6 and you get 3 so thats how subtracting helps but i think you get the point already. if you dont just let me know.
Adding and subtracting make a HUGE difference when it comes to recipes. For example, when baking if you add to much flour, than you dough would be to dry, but if you add to little flour to the recipe, then the dough would be very sticky.
