If $HCF(306, 657) = 9$,find $LCM(306, 657)$.

The decimal expansion of $\frac{18}{5^{3}}$ will terminate after how many decimal places?

For any two positive integers $a$ and $b$,what is the relationship between their $HCF$ and $LCM$? $\text{HCF}(a, b) \times \text{LCM}(a, b) = \text{?}$

For any positive integer $n$,the last digit of $5^n$ is always . . . . . . .

Every composite number greater than $1$ can be expressed (factorized) as a product of primes,and this factorization is . . . . . . apart from the order in which the prime factors occur. ($0$,$1$,unique)

If $P(-7) = 0$,then one factor of $P(x)$ is . . . . . . .