Wiktionary
count up
vb. to add to get a total
Usage examples of "count up".
Then I count up to ten and twelve, then drop to three or four, then mount to eleven at a leap.
By this means, if he was able to count up to one hundred, he could get our number correctly.
Doc Savage directed, and they hauled themselves out of the mud and climbed, boosting the big, bearded count up into the branches, helping Pat, the rest of them following hastily.