The method to divide fractions is to keep the first fraction the same, turn the divide sign into a multiply and turn the second fraction upside down. This is known as multiplying by the reciprocal.

Ah, math. It’s why I became an English major. But now math is spinning back around and haunting me in the form of my fifth grader. Last night, I found myself dealing with how to multiply fractions as ...

Numberphile revived an ancient multiplication trick—halves and doubles—also called Egyptian or Russian math, where you repeatedly halve one number and double the other. After crossing out rows with ...