Adding and Subtracting Mixed Numbers Unlike Denominators

Find Lowest Common Denominator & solve
1   3/7      +       7   5/11 =

• 8   68/77

• 8   68/107

• 8   10/77

• 8    8/18

Find Lowest Common Denominator & solve
4    1/2    +   14    6/12 =

• 18   7/14

• 18   12/12

• 18   24/24

• 18

Addition:
Find Lowest Common Denominator & solve
1    1/3   +    4    1/4 =

• 5    7/12

• 5    2/24

• 5    2/12

• 5    7/24

Find Lowest Common Denominator & solve
8     4/5    +    9    1/10  =

• 18   5/15

• 17   5/10

• 17   9/20

• 17   9/10

What is the sum?

• 
• 
• 
• 

• 10 7/12
• 11 1/9
• 10 5/9
• 11 5/12

Add or subtract to solve.

What is the sum of 2/3 and 1/5?

• 9/10

• 5/15

• 13/15

• 7/15

Is this a correct answer?

• Yes, the student correctly added.

• No, you cannot add unlike denominators

• No, 5 + 7 is not 12

• No, 2 + 3 is not 5

Subtraction:
Find Lowest Common Denominator & solve
8    5/7    -    7    2/3 = 

•   3/4

•  1/21

•    1/24 

•   3/24