I have a Recipe that calls for 1 cup of uncooked rice. Rice expands 3 fold during cooking. I have `2 1/2` cups of cooked rice. How much uncooked rice to I need to add to get the appropriate amount. To find how much rice I would have had, uncooked, I need to divide the volume of the cooked rice by 3. `2 1/2 -:3=5/2 -: 3/1=5/2 xx 1/3=5/6` I have the equivalent of 5/6 cup of uncooked rice. To find how much I need to add, I have to subtract 5/6 from one. `1-5/6=6/6 - 5/6=1/6` I need 1/6 cup of uncooked rice to complete my recipe.
There you have division and subtraction of fractions and mixed numbers. And this did actually happen to me just a few days ago.