Linkfest for Sunday, March 30

• Michael Pershan asks some good questions about how to approach the teaching of complex numbers.
• Fawn Nguyen has another Math Talk with her students. (I'm wondering if students think about which sorts of visual patterns will give a quadratic function and which will give a linear function.)
• OpenMathBook, a blog "to promote, discuss, and develop free and open source mathematics textbooks".
• Ihor describes a high school class recreating the experiment Eratosthenes conducted 2200 years ago. (Some day I want to try it...)
• Maria is conducting calculus math circles with 7 to 11 year olds. I am fascinated. My understanding of calculus is so steeped in algebraic thinking, it was hard for me to imagine at first. I love what she's doing.