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

If $p$ and $q$ are distinct prime integers,then their least common multiple $(LCM)$ is . . . . . . .

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.

The last digit of $2^5 \cdot 5^5$ is........

The $LCM$ of $7, 11,$ and $17$ is .......

If $HCF(a, b) = 1$,then $HCF(a - b, a + b)$ is equal to: