Definitions:

1. to be reasonable, logical, or comprehensible verb
   • The suspect's story did not add up.
2. to determine the sum of verb
   • If you add up all the mistakes, you'll see that it's insignificant.
3. to develop into verb
   • Hopefully this whole thing will add up into nothing.
4. to total the number or quantity verb
   • They began to add up the score.

Synonyms:

• amount
• make sense
• tally