As soon as the figure is divided by a hundred (4)
I believe the answer is:
once
'as soon as' is the definition.
(once can mean immediately after)
'figure is divided by a hundred' is the wordplay.
'figure' becomes 'one' (a numerical figure).
'is divided by' means one lot of letters goes inside another (inserted letters divide the word).
'a hundred' becomes 'C' (Roman numeral).
'one' enclosing 'c' is 'ONCE'.
'the' acts as a link.
(Other definitions for once that I've seen before include "... upon a time for the storyteller" , "In days gone by" , "not repeatedly" , "A single time" , "Cone (anag.)" .)