Why so complicated? Because our business is complicated. Take, for example, food cost. The basic formula for food cost is "(opening inventory + purchases - closing inventory) / food sales = food cost. Pretty simple. The formula breaks down to "cost of product divided by sales" which tells you what your food cost percentage is. But there are a lot of other variables that "can" play into this. Comps for one. Those often get taken out of food cost so they must be figured in. Sure you can make the argument that they do affect food cost so they shouldn't be taken out, but often, for accounting purposes they are a different line item and must be taken out, especially in many corporate places. The other reasons comps are often taken out is because the issues, that made comping appropriate, may not have been food related. Why should the kitchen take a hit on its budget if comps are made due to server errors or because of a promotion. Sure it effects the bottom line but often, in a P&L sheet, there is a more appropriate place for them. The same with employee/family meal. That cost should be taken out because, though it effects the bottom line, it really doesn't belong in food cost, and can make a difference if you are running close to budget. Then there are transfers, both to and from the kitchen. So now your food cost formula is "(opening inventory + purchases - closing inventory -cost of comps (which is price of comps / average food cost percentage) -cost of employee meal + transfers in -transfers out) / food sales = food cost percentage. Labor costing can get just as cumbersome sometimes, all depending on who you work for and how they handle their accounting. So you see, things can get complicated, at times. Do you need to be a math genius, no. Do you need a solid grasp of math to be an effective chef, most definately.