Since the late 1960s, well-meaning educators have shied away from placing kids in "faster" and "slower" classes. Now that trend is reversing—and for good reason.
A set of guidelines adopted by 45 states this year may turn children into "little mathematicians" who don't know how to do actual math.
Today's fashion is to throw away the textbook and to teach kids to think like mathematicians. The problem? They're not learning how to do actual math.