Question 889970
<pre>
9 Choose 6 = 9C6 = C(9,6) = {{{(matrix(2,1,9,6))}}} = 84

= {{{9!/(6!(9-6)!)}}} = {{{9!/(6!3!)}}} = {{{(9*8*7*6*5*4*3*2*1)/((6*5*4*3*2*1)(3*2*1))}}} =
  
  3  4
{{{(cross(9)*cross(8)*7*cross(6*5*4*3*2*1))/((cross(6*5*4*3*2*1))(cross(3)*cross(2)*1))}}} =  3*4*7 = 84

On a TI calculator

Press ON
Press CLEAR
Press 9
Press MATH
Press left arrow key <
Press 3
Press 6        See:   9 nCr 6
Press ENTER    See:        84

Edwin</pre>