Please assist & explain As I get stuck on converting to improper fraction

Question

A woman is 64 1/2 inches tall and her daughter is 57 7/9 inches tall. How much taller is the ​?

Answer 1

First examine the fractions for LCD.

1 / 2 and 7 / 9, LCD is 18

9 / 18 and 14 / 18

The problem now is

64 9/18 - 57 14/18

Now you borrow from the 64 and add to the 9/18, subtract and answer!

Answer 2

64 1/2 - 57 7/9

= 63 3/2 - 57 7/9

= 63-57 + 27/18-14/18

= 6 13/18 inches taller

or

64 1/2 = 64.5

57 7/9 = 57.777...

64.5000...- 57.777...

= 6.7222....

.7222...= 13/18

6.7222...= 6 13/18

or

64 1/2 = 129/2 = 1161/18

57 7/9 = 520/9= 1040/18

(1161-1040)/18 = 121/18=6 13/18