You have to bake a lot of brownies for your 6th grade fund raiser! Although you have plenty of flour, cocoa, milk, and oil, you only have 8 1 2 sticks of butter. You need to know how many batches you can make, based upon your limited amount of butter. You can cook partial batches to use up every bit of butter and make the most brownies possible. Each batch needs 3 4 of a stick of butter.