Question 470190
nCr=n!/((n-r)!r!)
63C7= 63!/((63-7)!7!)=63!/(56!7!)=(56!*57*58*59*60*61*62*63)/(56!*1*2*3*4*5*6*7)=(57*58*59*60*61*62*63)/(2*3*4*5*6*7)=553270671