“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.

There are some basic properties of whole numbers any 3rd grader can tell you: Each number is represented by a single symbol, and followed by a single successor. Multiplication makes a number bigger; ...

Fractions, often perceived as daunting, become manageable with the right approach. Addition and subtraction require finding a common denominator, while multiplication involves directly multiplying ...