Calling all number nerds: Put away your calculators! We have a problem that is sure to put your mathematical minds to the test. Do you think you have what it takes? (By the way, these habits prove you’re smarter than most, too.)

First, here is the equation: 9 – 3 ÷ 1/3 + 1 = ?

That’s it! Before you start, though, we should leave you with a brief warning. This equation may seem simple at first, but it’s way harder than it looks. In fact, only about 60 percent of the engineers got the correct answer on the first try, according to a Japanese study.

If your first instinct was to solve the problem from left to right, your guess is probably 3. But don’t forget to use the PEMDAS rule—’Please Excuse My Dear Aunt Sally,’ or ‘Parenthesis, Exponents, Multiplication, Division, Addition, Subtraction’—which gives the order in which to calculate each set of numbers.

The fraction adds another hurdle to this problem, too. Suddenly, what was once a simple equation now looks like a numerical nightmare. (The Internet can’t solve this third-grade math problem, either.)

Need a hint? TipHero suggests dividing 3 ÷ 1/3 first. Once you get that answer, solve the rest of the equation from left to right. If your final answer is 1, congrats! You are correct. But for those who are still stumped, you’re not alone. You can watch this entire video to see how they calculated the correct answer.

Whether or not you solved the equation on the first try, there is certainly more where that came from. See if you can solve this ‘simple’ math puzzle for children next. Then, test your knowledge with this elementary school math test.

[Source: TipHero]