The brain is a muscle that needs to be exercised just like every other muscle in the body, and puzzles and brainteasers are known for being the perfect way of keeping the brain active!

Now, a new puzzle is going viral, as it is leaving people all over the world stumped. To solve this puzzle, you don't need to have good math skills. Instead, you just need to have the ability to look at a sequence of numbers and identify what is missing from the grouping.

People have spent hours trying to figure out what is missing, but very few are getting it on their first try. The sequence of numbers is:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Here's What They're Not Telling You About Your Retirement

You have to think very hard to find the “mitsake” in this puzzle. Some are saying that the sequence is missing the number “0” or “16," but this is not actually a mistake.

We have the answer for you, but spend a few more minutes thinking about it before you read it!

Still stumped? Give it one more try!

Okay, here's the answer...

This Could Be the Most Important Video Gun Owners Watch All Year

The answer to this puzzle lies at the bottom, and editors and proofreaders will probably already know the answer. Whoever created it misspelled the word “mistake," spelling it as "mitsake!"

Trick questions like this are frustrating at times, but it's one of the best ways to exercise the brain and keep us on our toes.

Did you get this puzzle on the first try, or did it take you some time to figure it out? Let us know in the comments section!

The opinions expressed by contributors and/or content partners are their own and do not necessarily reflect the views of LifeZette. Contact us for guidelines on submitting your own commentary.