Totals left in disadvantaged areas (5)
I believe the answer is:
slums
'disadvantaged areas' is the definition.
'slums' can be an answer for 'areas' (I have seen 'Poor areas' mean 'slums' so perhaps 'areas' could also mean 'slums'). I am not sure about the 'disadvantaged' bit.
'totals left in' is the wordplay.
'totals' becomes 'sums' ('sum' can be a synonym of 'total').
'left' becomes 'l' (common abbreviation).
'in' means one lot of letters goes inside another.
'sums' enclosing 'l' is 'SLUMS'.
Can you help me to learn more?
(Other definitions for slums that I've seen before include "wretched dwellings" , "Rookeries no longer found in" , "Run-down city areas" , "Poor areas" .)