Find the sum of (3,2)
'find the sum of' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for add up that I've seen before include "Seem to be sensible" , "Total; make sense" , "Reckon" , "Ring true" , "Seem consistent or reasonable - arithmetically?" .)
(Other definitions for add that I've seen before include "Combine (numbers)" , "Tot; append" , "Include" , "Sum, total" , "Give more" .)