Q.4 Write the greatest 4-digit number and express it in terms of its prime factors.

The greatest 4-digit number = 9999
$$ \begin{array}{|l} \llap{3~~~~} 9999 \\ \hline \llap{3~~~~} 3333 \\ \hline \llap{11~~~~} 1111 \\ \hline \llap{101~~~~} 101 \\ \hline 1 \end{array} $$ Hence, the prime factors of 9999 = 3 x 3 x 11 x 101.