1. Fractions With Unlike Denominators
LESSON 5-3
Additional Examples
Find 1 3 1 2
Method 1 Model 1 2 3
Use the fraction model for . 1 2 3 = 1 2 3 5 6

2. Fractions With Unlike Denominators
LESSON 5-3
Additional Examples
(continued)
Method 2 Use a common denominator.
1  3
2  3 1 2 3 6 +
The LCD is 6. Write the fractions
with the same denominator.
1  2
3  2
Add the numerators. 5 6

3. Fractions With Unlike Denominators
LESSON 5-3
Additional Examples
In Ms. DeMarco’s class, of the students chose
cheese as their favorite pizza topping. Pepperoni was
chosen by of the students. What fraction of the students
chose either cheese or pepperoni as their favorite pizza
topping? 3 5 1
Add and to find the fraction of students who chose cheese or pepperoni. 3 5 1 1 3
1  5
3  5 + 5
The LCD is 15. Write the fractions
with the same denominator.
3  3
5  3 15 9
Add the numerators. 14 15
The favorite pizza topping of of the students is either cheese or pepperoni. 14 15

4. Fractions With Unlike Denominators
LESSON 5-3
Additional Examples
Find – . 5 8 1 6
Method 1 Model – . 1 6 5 8
Use the fraction model for . 1 6 5 8
– = 1 6 5 8 11 24

5. Fractions With Unlike Denominators
LESSON 5-3
Additional Examples
(continued)
Method 2 Use a common denominator. 1 6
1  4
6  4 – 5 8
The LCD is 24. Write the fractions
with the same denominator.
5  3
8  3 4 24 15
Subtract the numerators. 11 24