The Least Common Multiple $(LCM)$ of $6$ and $20$ is . . . . . . .

The last digit of $5^n$ is . . . . . . ,where $n \in N$.

Explain why $7 \times 11 \times 13 + 13$ and $7 \times 6 \times 5 \times 4 \times 3 \times 2 \times 1 + 5$ are composite numbers.

The form of any odd positive integer $a$ is .......... where $m$ is some integer.

If the Least Common Multiple $(LCM)$ of two numbers is equal to their product,then their Greatest Common Divisor $(GCD)$ is ........ .

For the decimal expansion of a rational number $\frac{p}{q}$ to be terminating,if $q = 2^m \cdot 5^n$,then $m, n \in$ . . . . . . ($R$,$N \cup \{0\}$,$Z$)