Flex your math muscles with this weekend’s brain teaser. Play now.

In order to solve a math equation in Messages, type the problem into your text field, add the equals sign (=) and the solution will appear in the predictive text field over your keyboard.

Mathematics is solving problems,” said Bethany Rittle-Johnson, a professor of psychology and human development at Peabody College in Vanderbilt University, who studies math instruction.

“It is a lot like a human,” Mr. Achim said. “If you are trying to solve a math problem, you try certain steps. And if they fail, you try others, until you get them right.” Image Harmonic ...