Mary is baking a cake. The recipe calls for w cups of sugar and some more cups of flour. She already put in x cups of flour. If she still needs to add y more cups of flour How many cups of flour did the recipe require?
First, we need to find out how many cups of flour the recipe requires. We know that Mary has already put in x cups of flour, and she still needs to add y more cups of flour. This means that the recipe must require x + y cups of flour. 

Now, we need to find out how many cups of sugar the recipe requires. We know that the recipe calls for w cups of sugar, and we also know that the recipe requires x + y cups of flour. This means that the recipe must require w + (x + y) cups of sugar. 

Therefore, the answer (symbolic expression) is: 

w + (x + y)