Geometry Practice Test 2

Any three points lying on a circle forms a triangle. Any four points lying on a circle forms a Quadrilateral.
How do we choose three points out of 8 and how do we choose four points out of 8?
$\stackrel{8}{}{\mathit{C}}_4-\stackrel{8}{}{\mathit{C}}_3$
$\frac{8!}{4!4!}-\frac{8!}{5!3!}$
$\frac{8\times 7\times 6\times 5\times 4}{4\times 3\times 2\times 1\times 4!}$ - $\frac{8\times 7\times 6\times 5!}{5!3\times 2\times 1}$
70 - 56 = 14