1 add an introduction to the book put on, put in, include, complete, improve, attach, supplement, combine, build on formaladjoin, affix, append, annex, augment colloqthrow in 2 add numbers count (up), total, work out/calculate the total colloqtot up 3 the rain added to her misery increase, raise, boost, intensify, deepen, heighten, extend formalaugment colloqhike up, aggravate 4 ‘Thanks,’ I added tack on, continue, go on, go on to say, carry on antonym 1 take away, remove, reduce, decrease 2 subtract, take (away), deduct, remove ■ add up 1 add up numbers add, sum up, add together, total, tally, count (up), reckon, calculate, compute, figure up colloqtot up 2 the total adds up to 100 amount, make, come to, run to, include, spell formalconstitute 3 it doesn't add up be consistent, hang together, fit, be plausible, be reasonable, stand to reason, make sense, mean, signify, indicate, ring true antonym 1 subtract