Recall that the notation $(\frac{N}{n})$ represents a combination of $n$ objects chosen from a larger sample of $N$ objects. This is calculated as follows. When $n=1,(\frac{N}{n})$ will always be $N.$

$(\frac{N}{n})=\frac{N!}{n!(N-n)!}\backslash$end$\{$array$\}]$