“Who would draw a picture to divide 2/3 by 3/4?” asked Marina Ratner, a professor emerita of mathematics at the University of California at Berkeley, in a recent Wall Street Journal opinion piece.

For many elementary teachers, fractions have traditionally sprung to mind lessons involving pizzas, pies, and chocolate bars, among other varieties of “wholes” that can be shared. But in what many ...

The Common Core State Standards have vaulted into the national consciousness lately thanks to some high-profile dissenters, like Louis C.K. ("Kids teachers parents are vocally suffering.") and Stephen ...