There's a song in the game Fallout 4 called Grandma Plays the Numbers. The full lyrics can be found at that link. It was written and performed by Wynonie Harris in 1949.
I'm not sure what is meant by the title. It sounds like it is probably some kind of gambling. Maybe the lottery?
If that's the case, then he's really making a big deal out of it. Was playing the lottery unseemly for old ladies in 1949?