Question 169228
You forgot the "r!" in the denominator.
C(n,r) = n!/(r!(n-r)!)
C(12,10) = 12!/(10!(12-10)!)
C(12,10) = 12!/(10!(2)!)
C(12,10) = (11*12)/(1*2)
C(12,10) = 132/2
C(12,10) = 66