Tot to make sense (3,2)
I believe the answer is:
add up
This clue is a double definition.
'tot' is the first definition.
(synonyms)
'make sense' is the second definition.
(synonyms)
'to' is the link.
(Other definitions for add up that I've seen before include "Sum - make sense" , "tot" , "Seem to be sensible" , "Aggregate, get total" , "Do sums" .)