I am going to start with two mixed fractions, change them to improper fractions and then add them. I want to start with 1 3/10 and 2 1/4 .

1 3/10 = 10/10 3/10 = 13/10

2 1/4 = 8/4 1/4 = 9/4

To add these fractions we need a common denominator. The denominators are 10 = 2 5 and 4 = 2 2, and hence the least common denominator is 2 2 5 = 20.

13/10 = 26/20 and 9/4 = 45/20

Thus

1 3/10 2 1/4 = 13/10 9/4 = 26/20 45/20 = 71/20