Question

Write the Rules to find LCM.

Answer 1

Rules to find LCM : There are two methods to find LCM :

• A. Division method
• B. Factor method.

Find LCM by division method :

Example 1. Find LCM of 12, 18, 27 and 36.

$\therefore \mathrm{LCM}=2 \times 2 \times 3 \times 3 \times 3=108$, Ans.

Example 2. Find LCM of $\frac{2}{3}, \frac{3}{4}$ and $\frac{4}{5}$

Soln. : $\frac{\text { LCM of } 2,3 \text { and } 4}{\text { HCF of } 3,4 \text { and } 5}=\frac{12}{1}=12$, Ans.

Find LCM by factor method :

Example 1. Find LCM of 8 and 20.

Soln. : factors of $8=2 \times 2 \times 2$

factors of $20=2 \times 2 \times 5$

$\therefore \mathrm{LCM}=2 \times 2 \times 2 \times 5=40$, Ans.