You have learned how pictures can help you add fractions. Let's think of two pies of equal size. The first is cut into four pieces. Someone eats three of them, leaving only one piece. This piece is one of the original four pieces, or 
of the pie. The second pie is cut into four pieces, too. Someone eats one of the pieces, leaving three. If you add the remaining pieces of these two pies, you get:
We can also use pictures to help us understand how to subtract fractions. Think of that first pie again. It was cut into four pieces. The four pieces make up the whole pie. We can write this as 
. The person who came and ate three pieces ate three of the four pieces, or 
. We can subtract just by thinking about what was left. The 
we started with minus the 
that were eaten leaves 
.
We can add fractions or subtract fractions without using pictures. The fractions in this lesson will have like denominators. This means that the two fractions that you'll add or subtract will both have the same denominator. When you add or subtract fractions with like denominators, you do not work on the top number and on the denominator the way you do when you multiply. When you add or subtract, you copy the denominator. Then you work on the top number. Let's add these fractions:
The answer will have a denominator of 4. Add the top numbers. You should come up with this:
Now let's try subtracting those two fractions. Remember, copy the denominator into your answer, and then subtract the top numbers.
