add up

verb

• To take a sum.

  "Add up the prices and find out how much it will cost."

• To accumulate; to amount to.

  "If you can save even a couple of dollars per day, it will add up to a lot over a year."

• To make sense; to be reasonable or consistent.

  "His story just doesn't add up. Why would he have been at the restaurant the day before the event?"