45!/(45-5)!5!
\(\begin{array}{|rcll|} \hline && \frac{45!}{(45-5)!5!} \\ &=& \dbinom{45}{5} \\ &=& \frac{45}{5}\cdot \frac{44}{4}\cdot \frac{43}{3}\cdot \frac{42}{2}\cdot \frac{41}{1} \\ &=& \frac{45}{15}\cdot \frac{44}{4}\cdot 43\cdot \frac{42}{2}\cdot \frac{41}{1} \\ &=& 3\cdot 11\cdot 43\cdot 21\cdot 41 \\ &=& \mathbf{1221759} \\ \hline \end{array}\)
45!/(45-5)!5!
\(\begin{array}{|rcll|} \hline && \frac{45!}{(45-5)!5!} \\ &=& \dbinom{45}{5} \\ &=& \frac{45}{5}\cdot \frac{44}{4}\cdot \frac{43}{3}\cdot \frac{42}{2}\cdot \frac{41}{1} \\ &=& \frac{45}{15}\cdot \frac{44}{4}\cdot 43\cdot \frac{42}{2}\cdot \frac{41}{1} \\ &=& 3\cdot 11\cdot 43\cdot 21\cdot 41 \\ &=& \mathbf{1221759} \\ \hline \end{array}\)