Do you think of yourself as a secret mathematician who’s a genius at solving hard math problems? This math brainteaser will have even the biggest number nerds scratching their heads.

*People’s Daily,China* tweeted out this math puzzle in which each picture represents a number.

Are you a math genius? Test your brain with this Chinese math puzzle. Did you get it right? (HINT: The correct answer is 16) pic.twitter.com/BpdFyzB73y

— People's Daily, China (@PDChina) November 30, 2017

These algebra problems might seem easy at first glance, but hold on. *People’s Daily* was nice enough to give away the answer before you began. If you didn’t get 16, you did something wrong. Take a closer look at the pictures—you probably missed a few key details. (You’d need to look closely to solve this easy math problem that baffled the Internet, too.)

Still stumped? We’ll walk you through it (like we did for this coffee brainteaser). For the sake of the explanation, we’ll call the shoes S, the cat C, and the whistle W.

The first equation sets up the whole math puzzle. Three pairs of shoes added together equal thirty. S + S + S = 30, so divide 30 by three. Each pair of sneakers represents the number 10. Easy enough.

Now the second equation is clearer. Sub the shoes out for a 10, and you’ll find out 10 + C + C = 20. Subtract 10 from each side, so C + C = 10. Each cat must represent the number 5.

Look closely at the next equation before you jump into it. In the third equation, there are *two* whistles in each line, but the final one only has *one* whistle. So 5 + 2W + 2W = 13. If 4W = 8, then each whistle represents the number 2.

OK, so that clears up a bit of the next equation—until you plug the numbers in. Sub S + C x W for 10 + 5 x 2. Remember your order of operations? Multiply first, then add. So 10 + 10 = 20. What went wrong? (Hint: It’s similar to this “simple” math problem for kids that has adults stumped.)

The key is in the cat’s clothes. In the second and third equations, the cat has a whistle around its neck—but not in the last one.

No need to go back and redo all your hard work. Just change the last equation to S + (C – W) x W. Now plug the numbers in: 10 + (5 – 2) x 2. Work your way through it. The equation goes to 10 + (3) x 2, then 10 + 6. Finally, you get 16—problem solved!

Ready for more? These printable crossword puzzles will test your smarts. The Internet can’t figure out how many triangles are in this picture—can you?