加法 (jiā fǎ) is the Chinese term for the mathematical operation of addition — combining two or more numbers to find their total sum. The first character, 加 (jiā), means 'to add' or 'to increase', and appears in verbs like 加入 (to join) and 加快 (to speed up). The second character, 法 (fǎ), means 'method', 'law', or 'rule', and commonly appears in words related to systems or procedures, such as 办法 (solution) and 语法 (grammar). Together, 加法 literally means 'the method of adding' — a precise, formal noun used exclusively in mathematical and educational contexts.

This word is taught early in primary math education and appears in textbooks, worksheets, and classroom instruction. It contrasts with other arithmetic operations: 减法 (jiǎn fǎ, subtraction), 乘法 (chéng fǎ, multiplication), and 除法 (chú fǎ, division). While colloquially people may say ‘加’ alone in casual speech (e.g., ‘五加三’), 加法 refers specifically to the concept or process of addition as a formal operation.