What does the cryptic crossword clue "Is 4 minus 3 two? Not a person answers (2,3)" mean?

The wordplay uses a deletion. NO (synonym="NO") + ONE (synonym="it’s") = NOONE The answer is NOONE.

Is 4 minus 3 two? Not a person answers (2,3)

Guardian Cryptic #29471 | 7 Down | 2024-08-26 flower