Question

What is the LCM of $7,10$ and $4$?

Answer 1

Express the given numbers as product of their prime factors to find the LCM

Given numbers, $7,10$ and $4$

$$\begin{gathered} 7=7\times 1=7^1 \\ 10=2\times 5=2^1\times 5^1 \\ 4=2\times 2=2^2 \end{gathered}$$

LCM can be calculated by multiplying the prime factors raised to their highest powers

$\therefore$ $LCM=2^2\times 5^1\times 7^1$

$=4\times 5\times 7$

$\therefore$ $LCM=140$

Hence the LCM of $7,10$ and $4$ is $140$