Question 466309
The combinations of 12 things taken 9 at a time which is sometimes
written as 12C9 , sometimes as <sub>12</sub>C<sub>9</sub>, sometimes as C(12,9),
and sometimes as {{{(matrix(2,1,12,9))}}}, and sometimes referred to as
"12 choose 9", and it always means

{{{12!/(9!(12-9)!) = (12*11*10*9*8*7*6*5*4*3*2*1)/((9*8*7*6*5*4*3*2*1)(3*2*1))=

(12*11*10*cross(9)*cross(8)*cross(7)*cross(6)*cross(5)*cross(4)*cross(3)*cross(2)*1)/((cross(9)*cross(8)*cross(7)*cross(6)*cross(5)*cross(4)*cross(3)*cross(2)*1)(3*2*1)) = (12*11*10)/(3*2*1)=1320/6=220}}}

Edwin