Trying to figure this out

You must make sure not to confuse the two:

Combinations[nCr]=n! / [(n-r)!.r!]. Example:75C5=75! / [(75-5)!.5!]=17,259,390.

Permutations[nPr] =n! / [n-r]!.       Example:75P5=75! / [75-5]! =2,071,126,800.

$\quad \frac{75\times 74\times73\times72\times71}{5\times4\times3\times2\times1}\\ = \frac{75}{5\times3}\times\frac{72}{4\times2}\times73\times71\times74\\ = 5\times9\times73\times71\times74\\=17259390$