This is a collection of math lessons posted in this blog. Most if not all of the lessons use the strategy teaching through problem solving or through mathematical investigation. I believe that school mathematics is about teaching students how to think mathematically first and learning the mathematics second so math lessons should be designed so that students are engaged in thinking mathematically. This is something that should not be left to chance.

- How to grow algebra eyes and ears
- How to teach the inverse function
- How to teach the derivative function without really trying
- How to scaffold problem solving in geometry
- What is a coordinate system?
- How to teach triangle congruence through problem solving
- Teaching the meaning of equal sign
- Geometry lesson: Collapsible chair model
- Teaching negative numbers via the numberline with a twist
- Introducing negative numbers
- Teaching with GeoGebra – Investigating coordinates of points
- Teaching simplifying and adding radicals
- Teaching with GeoGebra: Squares and Square Roots
- Teaching trigonometry via problem solving
- Introducing positive and negative numbers
- Teaching subtraction of integers
- Algebraic thinking and subtracting integers – Part 2
- Subtracting integers using tables- Part 1
- Teaching the absolute value of an integer
- Teaching with GeoGebra: Constructing polygons with equal area