Express the number $156$ as a product of its prime factors.

Express $140$ as a product of its prime factors.

Determine whether the rational number $\frac{77}{210}$ has a terminating or non-terminating repeating decimal expansion. If it is terminating,write down its decimal expansion.

The last digit of $2^{3} \times 5^{125}$ is . . . . . . .

Prove that the square of every integer is of the form $3m$ or $3m+1$,where $m \in \mathbb{Z}$.

Without actually performing the long division,find if $\frac{987}{10500}$ will have a terminating or non-terminating (repeating) decimal expansion. Give reasons for your answer.