Each number finished off (5)
I believe the answer is:
eaten
'finished off' is the definition.
(I've seen this in another clue)
'each number' is the wordplay.
'each' becomes 'ea' (abbreviation).
'number' becomes 'ten' (ten is a kind of whole number).
'ea'+'ten'='EATEN'
(Other definitions for eaten that I've seen before include "Polished off" , "Consumed" , "Upset" , "absorbed in the system" , "demolished, possibly" .)