1. Name ____________________________________ Date __________________
Mrs. Labuski / Mrs. Rooney Period __________ Lesson 5-7 Adding &
Subtracting Fractions with
Unlike Denominators
1
3
1 Find a common denominator for 3 and 5.
+5
1 5
3 15
1 3
Write equivalent fractions with 15 as the
+5 15 denominator.
8 Add the numerators.
15
Keep the denominator
Add or subtract. Write your answer in simplest form.

2. There are three grades in Kyle’s middle school—sixth, seventh,
and eighth. One-third of the students are in sixth grade and ¼ are
in seventh grade. What fraction of the school’s students are in
eighth grade?
_1
5
2_ of the students
Sarah is making a dessert that calls for cup of crushed cookies. If
she has already crushed cup, how much more does she need?
_1
1
0_