Do you hate being kept in the dark? An unsolved mystery can haunt you, rattling around in your brain like a ghost.

We may never get answers to some of history’s biggest mysteries, such as the truth about the Bermuda triangle, the location of Cleopatra’s tomb or the identity of Jack the Ripper.

But we have an enigma you can solve in minutes, and it may even help to keep your brain sharp. Brain teasers like this one may boost your language ability, memory and problem solving skills.

If you’d like to play detective, this mystery number brain teaser will require you to use both logic and math skills. Using only the numbers on the page as clues, you’ll have to decipher the identity of the final missing number.

Math games like this one may help keep your brain strong and flexible through development of new neural connections. Number games also may make you quicker at everyday calculations, from figuring out how many bags of Halloween candy to buy to making sure you get the right amount of change back at the store.

**Check out the bottom of the page for the correct answer.**

*Answer: 17 | The middle number equals the top number times the bottom number plus the left number times the right number.*

**Did you solve the mystery number puzzle? If so, please comment to clue us in on how you did, how long it took and what’s your favorite unsolved mystery.**

**What’s Next?**

Did you know that brain teasers like this can help keep your brain in shape? Learn more about strengthening your brain…

Fun! Took about a minute to see the number relationship.

That was fun. I’d say about 2 minutes or so to get the answer.

It took me ten seconds, but then, i am a math professor. Using the numbers 1 through 9 only once each, and using add, subtract, multiply and divide each once only, come up with the number 100. Santa Fe Ray

I tried adding two numbers and then the other two numbers and seen immediately that wasn’t correct. I multiplied two numbers and the other two numbers and that was the answer. Took me right under 2 minutes for solve. Makes ya think:)

Took ~5 minutes; being an avid backgammon player helped.

(1 x 3) + (4 x 5) = 23

Took me a little over 2 minutes but then I was watching the Seattle Seahawks beat up on the Arizona Cardinals while figuring it out.

More Please! Added the individual numbers mentally, hmmm, then tried multiplication across and then up and down, added the sums, and then smiled. A few seconds total, but enjoyable non the less. Don’t overthink the examples.

I substracted 30 from 43 & 13 from 30=17

It took longer to find a paper and pencil than to find the number.

It took me 20 seconds. To Larry and Gary. #1. 3 x 5 = 15. 4 x 7 = 28. 15 + 28 = 43. #2. 6 x 2 = 12. 2 x 9 = 18. 12 + 18 = 30. Therefore 3 x 4 = 12. 5 x 1 = 5. 12 + 5 = 17. Hope this helps clarify the answer. I love puzzles. Give us more!

Good brain teaser, send out more

30 seconds and done!

15 seconds. Fast with numbers slow on reading

good brain teaser but not time killer either.

Less than two minute Love puzzles like these!

Cool math puzzle took 45sec

I made it overly difficult with an answer 23

Difference between Top & right numbers = first number

Difference between bottom and left numbers X 3 = second number.

Took me 2minutes and 15 seconds to come up with the answer of 17. I really love math so I found this very easy. I my really did make me think.

I compared the first example to the second example. I came up with a theory on how they actually work. I looked at the puzzle and was able to solve it in a reasonable amount of time.

I would love to see more puzzles that require math skills!

Laurie,

So glad you enjoyed it! We have a few more brain teasers here, and also thought you might enjoy Find the Missing Numbers and What’s Your Number.

ABOUT 2 MIN. TOP TIMES BOTTOM + SIDE TIMES SIDE ADDED = MIDDLE

Love numbers…this one was easy.

I first did combinations of adding and subtracting before trying multiplying. Took me about 5 minutes.

Since 43 is a prime number, I could rule out multiplication to get the final equation. So all total, maybe 2 minutes.

Yep 19. Took about a couple minutes. Only because I did the math about 10 times because it seemed too obvious and though there was something I was missing.

Not sure what Larry Bowser and Gary Loper are saying ?

about 15 seconds to solve

I love it . It Was great. Help me so much. I need More like this. It got me going. Thanks.

My first thought was to operate on the numbers in some way. I immediately realized adding wouldn’t do it. So, I tried multiplying in pairs and adding and that worked. The trick to solving puzzles is the kind of strategies one has available to solving puzzles. Let me share a puzzle with you. Using all the numbers 1 – 9 form 2 3-digit numbers that add up to the last 3 numbers. There are 168 solutions to this problem. The real test is to see how many you can find.

I multiplied the 2 horizontal number and the 2 vertical numbers and added them together. Solved in less than 30 seconds.

the number is 17….took me 1 1/2 minutes to figure out

I solved in maybe two minutes. Please include more of these, please!

Great brain puzzle.

30 seconds… while watching TV

The solution took about 2 minutes. I tried adding all surroundin numbers first, then hit on multiplying opposite numbers and adding the results.

Nice!

I love puzzles and math. Took about 1 minute.

Took 2 mins. Enjoyed the challenge

I subtracted 30 from 43 and 13 from 30 about 2 minutes

17

It took just over a minute. Just adding and multiplying until it made sense.

Larry Bowser is right. The first 2 do not add up like you say.

About 1 1/2 minutes.

I actually solved the 2nd puzzle 1st. I times the 2 numbers across and the times the 2 numbers up and down. Once I had those numbers, I just added them together to get center number. About 3 minutes. Keep am coming!

the first two do not add up to the middle number so what do the first two have in common with the third.

Solved in about 3 minutes

I multiplied the cross numbers then added them together for answer. I love puzzles. Word search, what’s different, fill ins. Thank you I enjoyed very much. Please provide more. Oh, took less than a minute to solve.

I love these and my grandsons love to help with the challenge. More puzzles like these please.

It took about 2 minutes.

Give me more of puzzles like this one!!!!!!!!!

Missed the timer, but did just fine.