What is the Meaning of “=” (Equals)?
In one lecture on the distributive property I wrote the following equation on the board: 2(x + 3) = 2x + 6
One student asked “But what is the answer?” I did not at first understand what the student was getting at, and I asked her to explain. She said she was told in her previous math classes in high school that equations always have an answer, so what is the answer here? Then I realized that “equals” has actually two meanings. In one case if I write x + 2 = 6 then the answer is x = 4. But in the equation above, the right side is a transformation of the left side—a transformation into an equivalent but differently formatted expression. Since then, I always make my students aware of the different uses of the term “equals.”