The procedural meaning of the equal sign actually represents arithmetic thinking, which is also called procedural thinking. The core of arithmetic procedural thinking is to obtain or get an answer.

The relational meaning of the equal sign actually represents algebraic thinking, which can also be understood as a kind of structural thinking. The core of algebraic thinking is to discover relationships, clarify structures, and connect them.

Arithmetic thinking and algebraic thinking are two different ways of thinking. Algebraic thinking requires a higher level of abstract ability. Because of this, students will have great difficulties in the transition from arithmetic thinking to algebraic thinking.

Source: @soleypokes