Figure out number in Dante's work (7)
I believe the answer is:
inferno
'dante's work' is the definition.
(I've seen this before)
'figure out number' is the wordplay.
'figure out' becomes 'infer' (inferring is a kind of figuring out).
'number' becomes 'no' (abbreviation).
'infer'+'no'='INFERNO'
'in' acts as a link.
(Other definitions for inferno that I've seen before include "Hell - conflagration" , "Large dangerous fire" , "blazer?" , "(Fiery) Hell" , "hot spot" .)