What’s the LCM of $4,5$ and $10$?

Least common multiple $\mathbf{\left(}\mathbf{LCM}\mathbf{\right)}$.

$\mathrm{LCM}$ is the smallest number that is common in all the given numbers multiples.

Multiples of the given numbers $4,5$ and $10$ are,

Multiples of $4$$=4,8,12,16,\mathbf{20},24,28,32,36,40$

Multiples of $5$$=5,10,15,\mathbf{20},25,30,35,40,45,50$

Multiples of $10$$=10,\mathbf{}\mathbf{20},30,40,50,60,70,80,90,100$

It is observed that, $20$ is the smallest number that is common in all the given numbers multiples.

Hence, the $\mathrm{LCM}$ of $4,5$ and $10$ is $20$