One may be dressed up to them - by numbers? (5)

I believe the answer is:

nines

I'm a little stuck... Click here to teach me more about this clue!

'numbers?' is the definition.
(nine is a kind of number)

I can't explain the rest of the clue.

(Other definitions for nines that I've seen before include "In emergency, press three of these" , "Dressed to these is to be perfectly turned out" , "squares" , "Dressed to these and you're well-turned-out" , "Numbers to which one may be dressed up?" .)

I've seen this clue in The Globe and Mail.

Want a hint initially instead of a full solution? Install my app