A Wall Street Journal opinion article drew considerable attention to Common Core (CC) math standards—particularly the sixth-grade standard for fractional division— in early August. In it, math ...

“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 ...