Green’s Dictionary of Slang

numbers, the n.

[the SE numbers upon which one bets]

1. [late 19C+] (US gambling) a popular form of street gambling called Policy, which involves predicting a combination of the winning numbers (between 000 and 999) at a racetrack, esp. widespread in US black community.

2. attrib. use of sense 1.

In compounds

numbers-banker (n.) (also numbers-baron, ...king, ...man)

[1930s+] one who runs a numbers lottery.

numbers house (n.)

[1970s] the office where the numbers ‘racket’ is run.

numbers racket (n.)

[1940s+] laying odds and betting on numbers.

numbers runner (n.)

[1950s+] one who takes the money from individual bettors and who delivers any payouts.

In phrases

hit the number (v.) (also hit the numbers) [1930s+]

1. to make a successful bet on the numbers game.

2. to be successful, in a non-gambling context.