add up

US /æd ˈʌp/
UK /æd ˈʌp/
"add up" picture
1.

to make sense; to seem reasonable or logical

:
His story just doesn't add up.
The numbers don't add up, there must be a mistake.
2.

to calculate the total of several numbers or amounts

:
Can you add up these figures for me?
We need to add up the expenses for the trip.