Classroom Examples
Common symbol-string misunderstandings. The example discussed here was documented
by Guershon Harel (in press). The high school student in this example was attempting to solve
the inequality ((x -1)
2
> 1). When asked to explain how she arrived at x > 1, she responded that
“The solution to the equation (x -1)(x -1) = 0 is x = 1, x -1.” She then crossed out the three
equality signs and above each wrote an inequality sign >, noting that “ xis greater than 1." When
she was then asked to solve (x -1)(x -1) = 3, she wrote: “(x -1) = 3, ( x -1) = 3.” Harel notes
that