One of the legends of math relates to the invention of the coordinate plane system. The legend states that Descartes was inspired to invent this system after watching a fly move around on the ceiling over his bed. This post tells the story and points out its relevance for modern math teachers.

# Tag Archives: Cartesian coordinate system

# Not all variables are created equal

Variables do not all serve the same purpose. Making this clear helps students more deeply understand algebraic equations, such as the equation for a line. This post shows how to understand the two kinds of variables in the slope-intercept form of a linear equation.