There is a viral equation that is taking the internet by storm. You’re about to find out why it is considered a truly difficult challenge. Can you solve the equation?

We gave this math challenge to several people, with varying results. Apparently, even one math professor with a Ph.D. attempted to solve it as well. The answer she gave was quite different from the others. Before we dive into the tricky challenge itself, let’s explain the importance of math riddles.

According to Thoughts on Teaching Math*, “Mathematical riddles are actually more like logic problems which require mathematics to solve.*” Basically, you see a problem that needs to be solved. However, that problem requires some mathematics to solve equations. “*One good reason for using mathematical riddles is that they strengthen both reading and problem-solving skills. In addition, they encourage critical thinking skills and can provide motivation by making math fun.*“[1] Also, if you have children, teaching them math riddles has numerous benefits.

“*Math riddles are also beneficial for your child’s development. Research on “grit” or mental toughness shows that the ability to stick with demanding tasks can be a better predictor of positive outcomes than intelligence. When children fail, they have the chance to try again. Learning how to persevere after a failure, or in the case of a riddle, not getting the correct answer, is the essence of building grit. One nice feature of math riddles is that not getting the answer doesn’t have any consequences; through math riddles, kids can learn that failing is safe, which helps them take positive risks later.*“[2]

## Can you Solve Equation?

The math riddle we have for you today is quite challenging. And, it has created some division among those who have attempted to solve it. People seem to be reaching different answers. What do you think is the correct solution?

To begin, we need to take a look at the math problem above. We can see it reads “230 – 220 divided by 2 = ?” What do you think the answer is? According to the mathematics Ph.D. professor, the answer is 5! Do you think that is correct? Let’s take a look at the solution so we can solve the equation.

Firstly, you need to consider the order of operations. Otherwise known as PEMDAS/BODMAS. Consider Parentheses/Brackets, then Exponents/Orders, then Multiplication-Division, and finally Addition-Subtraction. This means we would do the division first and then move on to subtraction. **230 – 220 ÷ 2 = 230 – 110 = 120**

However, if you worked the math riddle from left to right without considering the order of operations, you would get the answer of 5. **(230 – 220) ÷ 2 = 10 ÷ 2 = 5**

How is it that a mathematics professor could say the correct answer is 5? Well, look more closely at the answer they gave. It wasn’t “5,” but “5!” The exclamation point matters here!

5! is actually a factorial. So, the answer of 5! is correct, although just plain 5 isn’t. Denoted by the exclamation mark (!). Factorial means to multiply by decreasing positive integers. For example, **5! = 5 ∗ 4 ∗ 3 ∗ 2 ∗ 1 = 120.**

By looking at this tricky math riddle, we can see that math is a truly fun way to give your brain a good workout! If you enjoyed this puzzle, give these ones a try below:

**Only Creative Thinkers Passed ‘IQ Test’ With Flying Colors****Here’s a Tricky Riddle That’s Confusing So Many People! Can You Solve It?****No One Can Spot The Little Frog Hiding Among These Rocks**

**Sources**

- “
*The Advantages of Using Mathematical Riddles.*” Thoughts on Teaching Math. January 8, 2018. - “
*The Universal Equation Of A Birds Egg.”*Thoughts on teaching Math. September 13, 2021 - “
*Discover how spending time on math riddles can help your child feel smarter and happier.*” Imacs. Imacs Staff. March 31, 2021.