“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.

A lot of students begin by finding a common denominator for the dividend and divisor when dividing by a fraction. And a lot of teachers intervene by saying, “Remember, you only need a common ...

The Hechinger Report covers one topic: education. Sign up for our newsletters to have stories delivered to your inbox. Consider becoming a member to support our nonprofit journalism. The Common Core ...