Q. 5. Write the smallest 5-digit number and express it in the form of its prime factors.

The smallest 5-digit number = 10000
$$ \begin{array}{|l} \llap{2~~~~} 10000 \\ \hline \llap{2~~~~} 5000 \\ \hline \llap{2~~~~} 2500 \\ \hline \llap{2~~~~} 1250 \\ \hline \llap{5~~~~} 625 \\ \hline \llap{5~~~~} 125 \\ \hline \llap{5~~~~} 25 \\ \hline 5 \end{array} $$ Hence, the required prime factors: 10000 = 2 x 2 x 2 x 2 x 5 x 5 x 5 x 5.