$LCM(15, 21, 35) = .........$

Prove that any positive odd integer is of the form $6m+1$ or $6m+3$ or $6m+5$,where $m \in N \cup \{0\}$.

The $\text{g.c.d.}$ (greatest common divisor) of two numbers is $16$ and their product is $3072$. Find their $\text{l.c.m.}$ (least common multiple).

The numbers in the form $3k \pm 1$ $(k \in Z)$ are $\ldots \ldots \ldots . .$

The largest number which divides $70$ and $125,$ leaving remainders $5$ and $8$ respectively,is

$2.031 \overline{2}$ is ............