The Least Common Multiple $(LCM)$ of the smallest prime number and the smallest composite number is . . . . . . .

Find the $HCF$ and $LCM$ of the integers $12$,$15$,and $21$ by the prime factorization method.

If $\frac{x^{3}-1}{p(x)}=\frac{x^{2}+x+1}{x-1}$,then $p(x) = \dots$

Check whether $6^n$ can end with the digit $0$ for any natural number $n$.

If a positive integer is of the form $3q + 1$,where $q$ is a natural number,then its square can be written in the form $3m + 1$. Is the statement true or false?

$3 + \sqrt{16}$ is a . . . . . . number. (Rational,Irrational,Negative integer)