Relatively Simple Math Problem Goes Viral, Stumps Everyone

At first glance, it looks easy. But it’s stumped many over the years, starting in Japan.

The problem went viral in Japan after a recent study found only 60 percent of people between the ages of 21 and 29 could get the correct answer–down from 90 percent in the 1980s.

Despite appearing simple, Presh Talwalker of Mind Your Decisions noted what had fooled most people.

“You should write an expression that groups one third as one group,” he says in the video.

“Three divided by one third is equal to nine, and now we have nine minus nine, plus one,” he added

The solution harkens back to an acronym some likely learned in school: BODMAS, or brackets, open; divide; multiply; add; and subtract, in that order.

It’s also known as PEMDAS, or parentheses first, exponents (ie powers and square roots) next, multiplication and division (left-to-right), and addition and subtraction (left-to-right).