Apparently, it’s some kind of gambling activity.
Any idea what???
Just a lottery, but run by your local criminal syndicate instead of the ever benevolent state.
To be more specific, the classic numbers game has people select three numbers. The various bets would be compared to a “random” number – I’ve seen it as the last three digits on the numbers of shares sold on the New York Stock Exchange, or the last three digits on the total handle on a particular track. Whoever got all three got a 600:1 payoff. Bets were low; the runners went from house to hour collecting bets each day.
Now there are legalized numbers, which are essentially the same, only you get worse odds.
No no, the OP meant those numbers that runners wear in races. 