Adding and Subtracting Fractions with Unlike Denominators

To add or subtract, two fractions must have...

• a monkey

• a common denominator

• unlike terms

• the same numerators

It took Gerard five-thirds of an hour to complete his math homework on Monday, three-fourths of an hour on Tuesday, and five-sixths of an hour on Wednesday. How many hours did he take to complete his homework altogether?

• It took Gerard a half an hour to complete his homework altogether.

• It took Gerard two and two-fourth hours to complete his homework altogether.

• It took Gerard three and one-thrid hours to complete his homework altogether.

• It took Gerard three and one-fourth hours to complete his homework altogether.

Westford's zoo has two elephants. The male elephant weighs 33/5 tons and the female elephant weighs 14/5 tons. How much more does the male weigh than the female?

Gail made 7/8 quart of lemonade. Her sister drank 1/4 quart of the lemonade. How much lemonade is left?

• 1 quart

What is the sum of these fractions?

• 4/5

• 3/20

• 17/20

• 4/20

What is the sum of these fractions in lowest terms?

• 4/5

• 3/20

• 17/20

• 4/20

Oliver swam three - sevenths of a mile on Saturday and two - sevenths of a mile on Sunday. Which day did Oliver swim farther and by how much?

• Saturday, by 1/7 of a mile 

• Saturday, by 5/7 of a mile 

• Sunday, by 1/7 of a mile 

• Sunday, by 5/7 of a mile

When the denominators are not the same, I must find a...

• common numerator

• common denominator

• equivalent fraction

• mixed number

What is the best common denominator for this problem?

• 5

• 2

• 20

• 10

What is the best common denominator for this problem?

• 6

• 8

• 24

• 48