I can write the ratio of brown to white as 2:3, or I can write the ratio of white to brown as 3:2. Both are correct, but I have to use the correct ratio when I want to find an equivalent ratio. Suppose you want to make a bigger recipe and you are using 12 tablespoons of brown sugar. Then your ratio would either be brown to white 2:3 = 12:x OR white to brown 3:2 = [ggfrac] x/12[/ggfrac]. Either brown sugar is always the first number in the ratio, or it is always the second number.