How to say "equation" in Japanese

• 方程式ほうていしきJLPT N2approx.Common
  nounCovers 'equation' in the mathematical sense, a statement with an equals sign to be solved, as in a math class. This is the default word for 'equation'.
  以下いかの方程式ほうていしきの解かいを求もとめよ。↗

  Find the solution to the following equation.
• 計算式けいさんしき
  nounMainly means 'formula' or 'method of calculation'; 'equation' is only a secondary gloss. It is often not the word you want for a mathematical equation, but suits expressions showing how to compute something.

Use 方程式 for a mathematical equation with an unknown to solve; use 計算式 when you mean a formula or method of calculation rather than an equation proper.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 方程式ほうていしきequation
• 計算式けいさんしきformula
• 式しきequation