Question

Use the prime factorisation method to find the LCM of the following groups of numbers:

$3,4and5$

Answer 1

Finding the L.C.M:

LCM of $3,4and5$ is the smallest number among all common multiples of $3,4and5$

By prime factorisation method,

$$\begin{gathered} 3=3\times 1 \\ 4=2\times 2\times 1 \\ 5=5\times 1 \\ LCM(3,4,5)=2\times 2\times 3\times 5=60 \end{gathered}$$

Hence, $LCM(3,4,5)=60$