A few years ago, two of the school districts I work with adopted new mathematics curricula–they each chose the one the other was abandoning. Golly, they could have saved a lot of money by simply boxing up all the teacher and student editions and swapping!
When student performance falls short of expectations, most educators seem to go hunting for new tools such as the ideal curriculum, the ideal personalized intervention program, the ideal iPad app, and so on.
But take a look at my post from last week, The Right Kind of Lazy for Math. What depth of math knowledge do teachers need to guide students in the deep number sense required for this kind of mathematical agility?