Why does it matter whether we state definitions carefully when we all know what particular geometric figures look like? What does it mean to say that a reflecti

Focuses on essential knowledge for teachers about proof and the process of proving. It is organised around five big ideas, supported by multiple smaller, interc

Are sequences functions? Why can’t the popular “vertical line test” be applied in some cases to determine if a relation is a function? How does the idea o

"A series for teaching mathematics."--P. [1] of cover.

Why are there so many formulas for area and volume, and why do some of them look alike? Why does one quadrilateral have no special name while another has severa