Sums up? (4)
I believe the answer is:
adds
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sums up</span>' is the definition.<br/ ><span class="explanation-format__explanation">('add' can be a synonym of 'sum up')</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for adds that I've seen before include "Contributes further" , "Finds the sum (4)," , "Reckons" , "Sums, totals" , "Does summer job" .)