You've already discovered that pictures can help you understand fractions. They can also be helpful when you want to know how to add the parts of a whole to the parts of another whole. A circular image can help you visualize the addition of parts and wholes. If you cut a cake into two equal parts, you have two halves, or 
. Remove one half. Now you have 
of the cake left. Add another cake of the same size. Cut it in half. You still have the two parts of the cake. These parts make up 
of the cake. If you add these pieces to the other cake, you get 
.
Imagine a cake cut into four pieces of equal size. If you remove one piece, 
of the cake will be left. What if you had another cake of the same size? Cut that up into four pieces. The cake is still whole. In other words, you still have 
of the cake. If you add the three pieces from the other cake, what do you get? Each piece of cake is 
of the cake. Add:
You have seven pieces of cake.
