1, the mathematical symbols represented by three horizontal lines are constants. This is an equal sign. Reading: Constant equals. For example: a ≡ B. Read: A equals B.

2. Constant equals sign is generally used when some parameter variables are constants or constant expressions, which always means that the relationship has nothing to do with variables. Also pay attention to the difference between = equals and ≡ constant equals.

3. The mathematical symbol represented by three horizontal lines is written as ≡, which is always equal to the relationship has nothing to do with the variable when some parameter variables are constants or constant expressions.