Definition of "add up"

add up

verb
third-person singular simple present adds up, present participle adding up, simple past and past participle added up
1. (transitive, of a numerical amount) To take the sum of; to total.
2. (intransitive) To accumulate; to amount to.
  Quotations
  It all keeps adding up / I think I'm cracking up / Am I just paranoid? / Or am I just stoned?
  1994, Green Day (lyrics and music), “Basket Case”, in Dookie
  The bus wound its way up into San Marino, passing through the various small castellos that add up to form the diminutive country, […]
  2016, Christopher Walker, The First 49
3. (idiomatic, intransitive) To make sense; to be reasonable or consistent.