Robin has 28 packages of gum and 13 packages of candy. There are 4 pieces in each package. How many pieces of gum does Robin have?
There are 4 pieces in each package of gum. So, if we multiply the number of packages of gum by 4, we will get the total number of pieces of gum. 

There are 28 packages of gum. So, if we multiply 28 by 4, we will get the total number of pieces of gum. 

28 * 4 = 112