First-grade calculation, say (3)

I believe the answer is:

sum

(Other definitions for sum that I've seen before include "Quantity of money" , "Total, add" , "Add together" , "pupils find it a problem" , "Total; problem" .)

I've seen this clue in the Universal.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.