using factorial in probability question

[resolved]

Okay I up graded to soft version 2017 07 10 (12066)

big difference.

in CAS

1-PERM(365,30) / 365^30 and 1- 365! / (335! * 365^30) gave me the same correct answer... great

but when in HOME

1-PERM(365,30) / 365^30 gave me the correct answer, same as in CAS

BUT
1- 365! / (335! * 365^30) gave me "0" zero --- so I think there still is a bug that needs to be fixed??? or "0" needs to be better defined as "overflow error" or whatever the secret meaning that 0 is suppose to mean

365! / (335! * 365^30) = 1 not sure what "1" secret message is suppose to mean either, but 1 - 1 would equal 0, so the above equation makes more sense...just not the correct answer....

Joe -- thanks very much for taking the time and giving me a better insight into the HP Prime