Is there a difference in usage between these words?
- 演算 (えんざん)
- 算出 (さんしゅつ)
- 計算 (けいさん)
演算 is an operation. When you apply an operation, such as a boolean NOT, you could use this word.
計算 is a computation, a calculation. Morally, it involves many operations. It is also the word for formal calculi in the scientific domain (such as "lambda calculus" or "pi calculus")
I never encountered 算出 and I therefore do not know its usage and nuances. However, a quick check on the internet give a few compound words where it appears to express the result (出) of a computation: 算出税額: calculated tax amount, and 算出金額: calculated amount.