I need the TI 83 process for this equation, step by step on entering data. nCr = n!/(n-r)!r!

I did the following using alternative format, but need steps to enter to calculate same results:

45C10 = 45!/(45-10)!(10!) =319,018,729

15C3 = 15!/(15-3)!(3!) =455

30C7 = 30!/(30-7)!(7!) =2,035,800

Taking455 (15C3)*2,035,800 (30C7)=9,626,289,000divided by319,018,729 (45C10).

P = 926289000 divided by 3190187286 = 0.29035568

P = 0.2904 (rounded 4th place).