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

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