Nov 22, 2006

## Pattern Recognition Brain Teaser

By: Caroline Latham

Here’s a puzzle to test your ability to find a pattern and test it against more data.

In this table, each row across follows the same pattern of numbers. See if you can discern the pattern and fill in the missing number in the bottom row. For added challenge (or competition), time how long it takes you to complete the puzzle. Then, pass it along to someone else and see if they can solve it faster. The slower one has to cook dinner!

7 | 4 | 8 |
---|---|---|

3 | 9 | 7 |

6 | 5 | 10 |

? | 8 | 4 |

Executive functions, like planning, and spatial processing are handled by your frontal lobes.

Have you solved it yet? If not, here’s a **hint**:

If you read your figures like words in the West,

then multiply your efforts and subtract the rest.

Keep reading for the **answer and solution**.

(7x4)-8 = 20

(3x9)-7 = 20

(**3**x8)-4 = 20

The answer is **3**.

More brain teaser games:

- Top 25 Brain Teasers, Games and Illusions
- Brain Teasers for each Cognitive Ability
- More Mind Teasers and Games for Adults of any Age

Sigh! Could not get this teaser either. However, I did get the clue (somewhat). But what I found interesting is when I did repeat mentally the explanation, my brain felt, how can I say, a sense of wellbeing, like it was being nourished. Are all brain teasers not created equal in this regard? I remember mental distress after doing other ‘brain teasers’ years back.

Hi Michelle, you are probably experiencing the release of dopamine and other neurotransmitters that create that sense of wellbeing as you identified a pattern. Which is why learning, brain teasers, trading successfully, and other “brain exercise” activities can be quite addictive!

A different application, but illuminating

http://www.sharpbrains.com/blog/2006/10/13/the-joy-of-giving-and-the-cognitive-and-emotional-health-project-the-healthy-brain/

Looked at the problem differently. I didn’t get your solution…but I had fun. I said 7+4+8=19

3+9+7+19

6+5+10=21

9+4+8=21

In trying to make a second “pair” that were equal I put 9 in your empty spot.

Well…I’v always been bad at math and any form of logic. But I had fun!

OOOPS…I can’t type either.

3+9+7=19 also “I’ve”

Maryanne,

While the dopamine rush that Alvaro mentions above happens when you solve the puzzle or understand the answer (the “aha!” moment), working through the puzzle is good brain exercise in and of itself (you’re getting challenging and novel mental stimulation). And you did your math correctly with a logical pattern, so you’re not that bad at either task! The typos … well those may be more due to a lapse in attention and hand-eye coordination. Keep working and having fun with it!

came up with something different, in terms of a relationship. subtract each number from 9, take the absolute value of this difference, and sum them, the total is always 8 ie. 7–9=-2=2 (absolute), 4–9=-5=5, 8–9=-1=1 so 2+5+1=8

similarly in the second and third rows, sum is 8. therefore the number in the fourth row can be either 7 or 11.

convoluted solution and non-unique.

wonder what that says abt my brain!

You’re right, that does follow a pattern! Both you and Maryanne are finding creative solutions, which is good exercise for your brain! I think it says that your frontal lobes are in good shape — good work!

This clue confused me:

If you do your figures from east to west,

wouldn’t that mean from right to left?

Goodness Randy — you’re right! I’ll change it now!

An alternate solution, since the problem doesn’t state that the numbers must be integers:

If the first number is greater than the second number, add them and then subtract the difference of the first and second number. This covers row 1 and row 3.

If the first number is less than the second number, then add them and then subtract one less than the difference. This covers row 2, and indicates 2.5 as a solution to row 4.

Joseph,

Interesting solution, but if you don’t know what the first number in line 4 is, how do you know which rule to follow (the rule for lines 1 & 3 or the rule for line 2)?

Caroline,

Luckily for me, there was no solution where the first number is greater than the second number.

Joseph,

You’re right. The solution for the first number being larger doesn’t make sense (I end up with 16=4). If the first number is smaller, it does work out, but I get 1.5 as an answer.

x+8-(8-x-1)=4

x+8–8+x+1=4

2x+1=4

2x=3

x=1.5

Nice solution! Complicated, but it works!

Caroline,

Right you are! Thanks for the correction.

1

11

21

1211

111221

312211

? whats next

perhaps

13112221?

good one!

i found a different solution

7*4=2 8

3*9=2 7

6*5=3 0, the important digit is only the last digit therefore

3*8=2 4, now 6 may have worked but each pair has an odd and an even number plus no pair is double digit.

Creative Michael! Following your rules, I get 3 and 8 as possible answers, without a way to choose one answer. In line 2, both 3 and 9 are odd, so keeping it even and odd in each line doesn’t work. If you can come up with another rule to make only one answer, it’ll work!

I didn’t get the correct answer. I got five. the way I came to this was by adding the first and third number in each row. then you take that answer and subtract 1 from the number in the “one’s” spot. excuse my lack of knowledge. the number 123 1 is the hundreds, 2 is the tens, and 3 is the ones. so subtract 1 from the ones place and I came to the answer 5.

I came up with 3 but I got it in a different manner. Here is the way I figured it out.

1. 7 x 4 = 28 and Subtract first number = 8

2. 3 x 9 = 27 and subtract the first number = 7.

3. 6 x 5 = 30 and subtract first number but since number can’t be zero make it 10.

4. 3 x 8 = 24 and subtract the first number = 4.

Although the 3rd rule doesn’t jive all that well it still works.

Pattern Recognition …C is the answer I picked.

i came up with

(7Ãƒâ€”4)-20 = 8

(3Ãƒâ€”9)-20 = 7

(5x6)-20 = 10

(3x8)-20 = 4

go figure..

dorks.

Hello Erin, I wish you the best in 2008, perhaps including a more willing attitude to take on challenges and, if you decide not to give it a try, not to insult other people in that defensive, unhelpful way. No one is perfect 🙂

Have a great holiday and we hope to see you around again.

I thought the exact same way as Michael, and icansure:

1. 7 x 4 = 28 and Subtract first number = 8

2. 3 x 9 = 27 and subtract the first number = 7.

3. 6 x 5 = 30 and subtract first number but since number can’t be zero make it 10.

4. 3 x 8 = 24 and subtract the first number = 4.