# What is 5 equal to?

Can you find what corresponds to 5?

If: $$1=5$$ $$2=6$$ $$3=7$$ $$4=8$$

then, $$5=?$$

Note: the answer is not 9.

1, due to symmetry (thanks for the correction, @Peter!!) of the equals sign?

• Why are my puzzles so easy for you?! – Wais Kamal Sep 11 '18 at 11:50
• @WaisKamal Because El is short for Elite :D – Mr Pie Sep 11 '18 at 11:56
• @user477343 good point! – Wais Kamal Sep 11 '18 at 12:00
• I think you mean symmetry, instead of commutativity. – Peter Sep 11 '18 at 15:20
• Thanks @Peter, that I do. Will credit you and update the answer! – El-Guest Sep 11 '18 at 15:31

It is:

? (question mark), that's by definition.

• Good thinking! (though not the right answer) – Wais Kamal Sep 11 '18 at 11:50
• I don't mind downvoting but what is wrong with my answer to make you do that? – rhsquared Sep 11 '18 at 11:57

22, using the OEIS sequence A098670

or literally,

not 9.

• I don't understand that sequence. The $a(n)$'th digit of WHAT is a 2? Is there something missing in the description? – Vincent Sep 11 '18 at 15:20
• @Vincent - the $a(n)$'th digit of the sequence itself. The sequence starts with 5, must be growing as slow as possible, and (since it starts with 5) its 5th digit must be 2. Hence 5, 6, 7, 8, 22... work from there. – Neo Sep 11 '18 at 15:53

Well, since the first equation says:
1 = 5
I would say the solution is:
5 = 1

• Damn, @El-Guest got there first, buddy. That rule is lame, in my opinion. This is about puzzling, not some kind of competition :\ – Mr Pie Sep 11 '18 at 11:47
• Oh, shame on me :( – npkllr Sep 11 '18 at 11:49
• Correct answer but as stated by @user477343, El-Guest answered first. I will upvote all answers, but accept the one that came first. – Wais Kamal Sep 11 '18 at 11:52

its-

1, assuming $=$ signs work as they normally do, if $1=5$ then $5=1$ would be true

• El-Guest got it first – u-ndefined Sep 11 '18 at 11:54

It is

13. Replacing 5 with 1+4 or 2+3 and substituting those numbers from the given list, we find 5+8 or 6+7. Both equal 13.

For mathematicians, it could be :

$5=1$

Because,

$n_1 = n_2 [5] + 1$

As a result :

$1 = 5[5] + 1 = 0 + 1$

As well as

$2 = 6[5] + 1 = 1 + 1$

And

$4 = 4[5] + 1 = 3 + 1$

Finally :

$5 = 5[5] + 1 = 1$

Using :

As,
1 = 5

So,
5 = 1
Note: the answer is not 9.

1 = 5
Therefore, 5 = 1
That would not be true if polynomial of certain degree was given.

• Welcome to puzzling.SE! Not bad, but this is basically what the accepted answer is saying. – xhienne Sep 13 '18 at 9:27