Add Mixed Numbers with Unlike Denominators

To add mixed numbers, we first add the whole number parts together, and then the fraction parts.

For example: Let's find the sum of:

5 5 7

+

2 1 4

Add the whole parts.

 

5 + 2 = 7

 

Now, add the fraction parts.

 

5 7

+

1 4

Find the least common multiple of 7 and 4.

Least common multiple of 7 and 4 is 28.

 

So, least common denominator = 28
 

Now, rewrite both the fractions with denominator 28 .

 

5 7

×

4 4

=

20 28

1 4

×

7 7

=

7 28

Now, add:

5 7

+

1 4

=

20 28

+

7 28

=

20 + 7   28

=

27 28

Now, write the sum of whole parts and fraction parts together.

7

27 28

 

So, the required sum is

7 27 28

.