Number divided by a hundred, one makes an impression (6)
I believe the answer is:
etcher
'one makes an impression' is the definition.
'number divided by a hundred' is the wordplay.
'number' becomes 'ether' (I've seen this before).
'divided by' indicates putting letters inside.
'a hundred' becomes 'c' (Roman numeral).
'ether' placed around 'c' is 'ETCHER'.
(Other definitions for etcher that I've seen before include "One making an impression" , "Maybe she makes engravings" , "Cutter" , "Artist who likes to make an impression?" , "Artist using acid on metal" .)