Adding Fractions with Unlike Denominators

Find a common denominator for 1/3 and 1/4.

• 12

• 7

• 10

• 15

Convert 2/5 to an equivalent fraction with a denominator of 20.

• 8/20

• 6/20

• 10/20

• 12/20

Add 2/7 and 3/8.

• 5/15

• 1/4

• 4/15

• 37/56

Simplify 4/12 to its lowest terms.

• 2/6

• 1/3

• 5/15

• 6/18

Understand the concept of least common multiple in finding a common denominator.

• Divide the denominators by the smallest prime factor to get the LCM.

• Add all the denominators together to get the LCM.

• Subtract the denominators to find the LCM.

• Identify prime factors, take highest power of each prime factor, multiply these highest powers together to get LCM.

Find a common denominator for 3/5 and 2/9.

• 36

• 27

• 15

• 45

Convert 1/6 to an equivalent fraction with a denominator of 18.

• 5/18

• 3/18

• 4/18

• 2/18

Add 5/11 and 4/9.

• 89/99

• 9/20

• 7/15

• 1/3

Simplify 6/15 to its lowest terms.

• 4/10

• 2/5

• 1/3

• 3/5

Understand the relationship between denominators and common multiples.

• Calculate the least common multiple of two denominators.

• Identify the relationship between denominators and prime numbers.

• Understand the relationship between numerators and common multiples.

• Understand the relationship between denominators and common multiples.