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

If $k_{1}$ and $k_{2}$ are two distinct prime integers,then their $\text{l.c.m.}$ is ..........

If $a$ and $b$ are two odd positive integers such that $a > b,$ then prove that one of the two numbers $\frac{a+b}{2}$ and $\frac{a-b}{2}$ is odd and other is even.

The conjugate surd of $3+\sqrt{2}$ is $\ldots \ldots \ldots \ldots .$

The smallest positive number divisible by every integer from $2$ to $6$ is..........

$\frac{47}{500}$ has $\ldots$ digits after the decimal point in its terminating decimal expansion.