Yo-Yo Math
When schools or states are willing to change their textbooks every other year, as publishers tempt teachers with free resources (and bribe them with airline and cruise tickets).
Getting an entire state to adopt a publisher's set of textbooks is worth millions of dollars, so the sales and marketing personnel would go all out to play yo-yo math with decision makers to get them to choose their titles over those of their competitors.
Yo-Yo Math by MathPlus July 26, 2017
