Since the beginning of time, people have always loved a good brain teaser. We grew up reading Where’s Waldo? books and putting together puzzles. Though highly frustrating at times, we just can’t seem to resist a good riddle, challenging crossword, or game of sudoku

In the age of the internet, brain games, riddles, and optical illusions are spread around the world quickly, causing frustration, eye rolls, and proud exclamations of “I did it! I figured it out!” in their wake. The latest of these is a seemingly simple math problem that’s got a lot of people stumped.

Can you solve this math problem without a calculator?
Now, if you’re anything like me, math was not your strong suit in school. As soon as I was able to make math a part of my past, I did. Anytime I need to do some quick math, be it calculating a tip or how many pounds my 50-kg baggage allowance is at the airport, I have to whip out my calculator.

For many of us, it has been years since we have thought about the rules of mental math. See if you can figure out the answer to the equation below. The answer is below, but don’t peek until you’ve tried!

…104

If you didn’t get the correct answer, you’re not alone. As I said already, clearly many of us have forgotten the rules of basic math.

It’s time to think way back to grade school. What rules did your teacher give you in regards to the order in which equations like this are completed? (Hint: there’s an acronym that may help you out!) Use that and go try again.

The Order of Operations for solving math equations
Still struggling? Don’t forget the acronym for the Order of Operations: BEDMAS (or PEMDAS or BODMAS – depending on where you are in the world).
B – brackets
E – exponents
D – division
M – multiplication