This tricky math problem went viral a few years back after it appeared on an entrance exam in Hong Kong… for six-year-olds. Supposedly the students had just 20 seconds to solve the problem!

Believe it or not, this “math” question actually requires no math whatsoever. If you flip the image upside down, you’ll see that what you’re dealing with is a simple number sequence

This problem shouldn’t be too difficult to solve if you play a lot of sudoku.

All of the numbers in every row and column add up to 15! (Also, 6 is the only number not represented out of numbers 1 through 9.)

This problem comes straight from a standardized test given in New York in 2014.

You’re forgiven if you don’t remember exactly how exponents work. In order to solve this problem, you simply need to subtract the exponents (4-2) and solve for 3², which expands into 3 x 3 and equals 9. And for more questions that will challenge your rudimentary knowledge, check out these 30 Questions You’d Need to Ace to Pass 6th Grade English.

This question was used in China to identify gifted 5th graders. Supposedly, some of the smart students were able to solve this in less than one minute.

In order to solve this problem, you need to understand how the area of a parallelogram works. If you already know how the area of a parallelogram and the area of a triangle are related, then adding 79 and 10 and subsequently subtracting 72 and 8 to get 9 should make sense—but if you’re still confused, then check out this YouTube video for a more in-depth explanation.

YouTuber MindYourDecisions adapted this mind-boggling math question from a similar one found on an elementary school student’s homework in China.

Image via YouTube

Since one measurement includes the cat’s height and subtracts the turtle’s and the other does the opposite, you can essentially just act like the two animals aren’t there. Therefore, all you have to do is add the two measurements—170 cm and 130 cm—together and divided them by 2 to get the table’s height, 150 cm. And while you’re testing your smarts, check out these 30 Real Trivial Pursuit Questions You Need to Be a Genius to Answer Correctly.

If you’re having trouble reading that, see here:

“Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is. Cheryl gives them a list of 10 possible dates.

May 15           May 16           May 19

June 17           June 18

July 14            July 16

August 14       August 15       August 17

Cheryl then tells Albert and Bernard separately the month and the day of her birthday respectively.

Albert: I don’t know when Cheryl’s birthday is, but I know that Bernard doesn’t not know too.

Bernard: At first I don’t know when Cheryl’s birthday is, but I know now.

Albert: Then I also know when Cheryl’s birthday is.

So when is Cheryl’s birthday?”

It’s unclear why Cheryl couldn’t just tell both Albert and Bernard the month and day she was born, but that’s irrelevant to solving this problem.

Confused about how one could possibly find any answer to this question? Don’t worry, so was most of the world when this question, taken from a Singapore and Asian Schools Math Olympiad competition, went viral a few years ago. Thankfully, though, the New York Times explains step-by-step how to get to July 16, and you can read their detailed deduction here.

This one comes from a first grader’s homework.

When you add together the values given for S, B, and G, the sum comes out to 40, and making the missing letter J (which has a value of 14) makes the other diagonal’s sum the same.

Try to figure out what all of the equations have in common.

The formula used in each equation is 4^x = Y. So, 4¹ = 4, 4² = 16, 4³ = 64, and 4⁴ = 256.