Quiz! Find the number

[webgift]

Let's play for a while! Find out the missed number from the image below. Don't explain how. Just write the number.

[datahell]

90!

[webgift]

Any other? When we collect up to 5 answers i will request you to analyze your answer by sending me a Private Message. Any who answer correctly and analyze his reply in detail will be the winner of this quiz! 

[michalis1984]

It's 90. Mine solution is at your mailbox 

[webgift]

Ok Michalis! I got your reply however I will answer when i am ready. Till then let's look the follow patent. 

[Ivan Trebješanin]

72

I thought it was too simple, so everyone will answer with ease.

[datahell]

This is not a patent, this is how you make bombs (raki) in Crete :-)

[webgift]

Hahaha we don't make bombs! If we create such things then i would be a nuclear one. Raki (or otherwise: Tsikoudia) is sanctification for us.      We create it like this:


  . Just a joke.

[webgift]

Hello Ivan! I slightly modified your answer in order not affect the other members. Of course i will be waiting your analytic reply to my private inbox.

[datahell]

The obvious answer is 90. 72 can also be explained although 90 is I believe the most correct from a mathematical point of view. 72 is for "visual" guys.
90 is definitely a right answer, so no matter what other solution might exist, 90 is also correct!

[webgift]

Please don't discuss something else about it till tomorrow morning. Till the time come! 

[nikos]

The right answer by me is 90

With a first quick look seems to be 72 but looking better you can see that from row numbers are missing 7 and 8 which also must calculate their result to reach the result of 9

[webgift]

Ok the time has come, so i am ready to send the solution for this quiz!
The solution is a combination of mathematics (=logic) and imagination (=observation). It's not all mathematics or imagination anyway. However you should consider that the solution won't be the obvious one.

And the absolute winner is : Nobody. 

The only one who answered correctly but his analyze of the answer was not the correct one is: Ivan Trebješanin. Congrats Ivan!!! you are a half - winner! 

-- The solution --
1. Stay focused on the image
2. As you can see it is not displayed the following...
0 = 0
1 = 2
...
7 = 56
8 = 72
If all of these cases are displayed then the solution would be the mathematical (=logical) one which is: 9*10 = 90.

3. Now why the following thought is wrong:
2*3 = 6
3*4 = 12
4*5 = 20
5*6 = 30
6*7 = 42
7*8 = 56
8*9 = 72

With this thought the 7 number would be equal to 42 or 56, the 1 number would be equal to 0 or 2. So why the 5 number is equal with 30 and not equal to 20?



Here is the answer..
We have :
2 = 6
3 = 12
4 = 20
5 = 30
6 = 42

Each time we multiply the left number with the left number + 1.
The number in left : 2, 3, 4, 5, 6, 9
So the sequence is: 3, 4, 5, 6, 7, 8
Finally the solution by keeping the sequence below is: 9 x 8 = 72!

[datahell]

This is one of the solutions. I disaggree regarding 90 which I believe is the correct answer.

2 = 6
3 = 12
4 = 20
5 = 30
6 = 42
The above gives you a sequence from which you can calculate the result for any next number. The result is the difference of the previous 2 results + last result + 2.
So:
7 = (42 - 30) + 42 + 2 = 56
8 = (56 - 42) + 56 + 2 = 72
9 = (72 - 56) + 72 + 2 = 90
10 = (90 - 72) + 90 + 2 = 110
etc ...

[webgift]

I repeat you see the result as a mathematical point of view! That's why we call it quiz. Do you want to give you one more mathematical explanation? Why the result not to be:  the addition of the previous result + 2 in to [Χ] each time. Where X is the left part.
1 = 2 = (0+2) = (0 + 2*1)
2 = 6 = (2+4) = (2 + 2*2)
3 = 12 = (6+6) = (6 + 2*3)
4 = 20 = (12+8) = (12 + 2*4)
5 = 30 = (20+10) = (20 + 2*5)
6 = 42 = (30+12) = (30 + 2*6)
7 = 56 = (42+14) = (42 + 2*7)
8 = 72 = (56+16) = (56 + 2* 8 )
9 = 90 = (72+18) = (72 + 2*9)