In the episode, Sam makes a bet for Norm in Atlantic City. He bets $50 on "black 17" at the roulette tables...and hits. Then, while distracted by his date, Sam leaves Norm's winnings on the table for another bet...which hits again. Hitting an exact number at the roulette tables pays 35 to 1. So--$50x35=$1750 in winnings. Then, his $1750 in winnings left on the table again hitting and paying 35-1=$61,250. So back the bar, presuming that taxes were not automatically withheld, Sam hands Norm a check for $61,250 (which may or may not have covered Norm's bar tab).
Frasier refers to his and Lilith's fifth wedding anniversary. As time is often compressed in a television series, it is here as well. Their marriage took place on S6/E17 (aired February 11, 1988) and the present episode (S10/E20) was aired four years later on February 27, 1992.