# Finding the least common multiple

LCM, the least common multiple, is the smallest positives integers that is a multiple of two integers e.g. x and y. A multiple is a product of a number, if two numbers has one or more multiples in common they are called common multiples. The LCM must be determined before two fractions can be added or subtracted.

Example:

$\\ \frac{8}{12}+ \frac{2}{6}\\\\ 12=2\cdot 2\cdot 3\\ \, \: 6=2\cdot 3\\\\ LCM=2\cdot 2\cdot 3=12\\\\ \frac{8}{12}=\frac{8}{12}\\\\ \frac{2}{6}=\frac{2\cdot 2}{2\cdot 6}=\frac{4}{12}\\\\ \frac{8}{12}+\frac{4}{12}=\frac{12}{12}=1 \\$

Video lesson: Find the answer to

$\frac{2}{9}+\frac{3}{6}$