Synonyms for add

verb

1. To combine numbers into a sum

   total, sum, sum up, figure, figure up, compute, calculate, do a sum, tally, count up, foot up, cipher up, add up, cast up, do simple addition, run over, enumerate, reckon, tell off, score, tote up*.

   Antonyms subtract, decrease*, take away.

2. To join so as to increase

   append, annex, supplement, affix, attach, unite, combine, superimpose, tack on, hitch on, clap on*; see also join 1.

3. To make a further remark

   say further, continue, write further, append, add a postscript, reply, go on.