Robin has w packages of gum and x packages of candy. There are y pieces in each package. How many pieces of gum does Robin have?
First, we need to find out how many packages of gum Robin has. We know that Robin has w packages of gum and x packages of candy. This means that Robin has w + x packages in total. 

Now, we need to find out how many pieces of gum Robin has. We know that there are y pieces in each package, so Robin must have y * w pieces of gum. 

Therefore, the answer (symbolic expression) is: 

y * w