Math Problem That Looks Simple Leaves People Baffled Over the Right Answer

By Zachary Stieber

A math problem that looks simple at first glance has left social media users confused over the correct answer, with some insisting they’ve gotten it right.

The viral math problem is as follows: 8 divided by 2(2 + 2) = ?

The problem appeared to first be posted by a Twitter user, who asked followers to solve it.

Since then, it’s spread across social media websites and stumped many people who tried.

Some people have claimed the correct answer is 16 while others opted for other numbers such as one.

Hannah Fry, an associate professor in the mathematics of cities at the Center for Advanced Spatial Analysis at University College London, told the Daily Mail that there’s an issue with the problem.

“The problem with it is that the way it’s written leaves room for ambiguity over the answer,” she said.

“The (2+2) in brackets is easy enough to deal with—it’s equal to four. But then what does the rest of the equation mean? Is it 8÷(2×4) =1? Or is it (8÷2)x4 = 16? This is like a maths version of the sentence ‘He fed her cat food.’ Does it mean the man gave some food to a cat? Or—slightly darker—fed some cat food to a woman. It’s impossible to tell from the information we’ve been given.”

She said whoever came up with the problem should have placed the 8 over the top of the 2(2 + 2) portion or placed it in a second configuration that would have seen 8 placed on top of the 2 with the other part separate.

The fraction in the equation forces people writing equations to be clearer about they mean, Fry said, claiming that “both one and 16 are correct, depending on how you interpret it.”

“But also, neither of them are, because it’s just a badly written equation,” she added.

Other math experts said there was a correct answer.

Kelly Morenzoni, a high school math teacher in New York City, said the right answer would be 16.

“What a lot of people want to do is multiply two by two to then get 4. And then ultimately divide eight by eight to get one. Which is not the correct answer,” she told WDAF-TV.

“Because multiplication and division and addition and subtraction are inverse operations, when they come right beside each other, you do them in the order in which they appear.”