Example of Subtraction of Fractions:
1/3 + 1/6 + 1/8 = ____
Using trial & error we could search that 24 is the LCD or smallest number in which 3, 6, and 8 will all divide within evenly. Thus, if each fraction is converted into 24^{ths}, the fractions can be added.
1/3 .(8/8) + 1/6 . (4/4) + 1/8 . (3/3) =
8/24 + 4/ 24 + 3/24 = 15/24
This is the easiest form the fraction could have. To eliminate the lengthy procedure of trial and error used in searching the LCD, you can reduce the denominators to their prime numbers.