Stage 5: Justify thinking. A vital habit that many students need to solidify is recontextualizing after they solve ...

We illustrate a method, which is modeled on "breaching experiments," for studying tacit norms that govern classroom interaction around particular mathematical content. Specifically, this study ...

Match word problems, visual models, and expressions & equations. Warm up with a Mystery Math Mistake as you add two 2-digit numbers using a decomposition strategy. Find Which One Doesn't Belong to ...

"Even the +, −, =, and x signs we take for granted only came into widespread use in the 17th century. Which means that the earlier algebraists we know of … all had expressed their equations mostly in ...