연산이 · 연산을
computation, calculation; (math) operation
Example
컴퓨터는 복잡한 연산을 아주 빠르게 처리합니다.
Computers process complex calculations very quickly.
Word parts
연 perform+산 calculate
Literally 'carry out a calculation.'
Good to know
연산 is the technical word; in everyday talk about money or numbers, use 계산.