Find the LCM of $12,18,20,25$.

Prime factorization of the given numbers:
* $12=2^2\times 3$
* $18=2\times 3^2$
* $20=2^2\times 5$
* $25=5^2$

The $\text{LCM}$ is the product of highest powers of all prime factors present:

$$\text{LCM}=2^2\times 3^2\times 5^2=4\times 9\times 25=100\times 9=900$$