How do I solve 2 down in Daily Telegraph Cryptic 31272?

Question

Accepted Answer

2 down reads "Book for anaesthetists?" (7 letters); the answer is NUMBERS. It's a double-definition clue: two separate definitions of the same word sit side by side. No wordplay split and no indicators — both halves of the clue define the answer. The full step-by-step breakdown is on this page.

Book for anaesthetists? (7)

2D — Book for anaesthetists? (7) — NUMBERS