# Find this number

Which number am I?

We are searching for a number.

It is over 400 years old.

Even longer ago there were people who said it wouldn't be so hot on your tongue.

Hint

It is a four digit integer.

Note: I thought of this myself. Because English is not my mother language I would really like to see a better phrasing or even the same riddle in poem form.

• Thoughts hinted at number 5 (in the form of two forked fingers, forming letter V, a roman five) but it did not fully justify! – Mea Culpa Nay Dec 7 '17 at 14:01
• You are getting closer with that! – Tweakimp Dec 7 '17 at 17:04
• Are you sure there is no knowledge needed. – ibrahim mahrir Dec 7 '17 at 19:48
• @ibrahimmahrir Pretty sure. – Tweakimp Dec 7 '17 at 19:53
• Just a note in ROT13 ZVYQ vf abg n Ebzna ahzreny – Tom Dec 7 '17 at 21:18

Is it:

MILD in Roman numerals, or 1449

Because:

1449 was well over 400 years ago, and people have been using hot peppers in food for over 6000 years, hence the comparison between hot and 'mild' food which is not hot on the tongue?

• This is definitely the best answer so far – Sam Hazleton Dec 7 '17 at 19:58
• Exactly! Well done! – Tweakimp Dec 7 '17 at 20:07
• @Tweakimp Is there any particular reason for "over 400" specifically? Seems like 500/300 would have done just as well. Just to be a little vague? – Miles Dec 8 '17 at 21:24
• @Miles Initially I wanted to go with MDLI, 1551, because that is the only numeral you can make with these letters with the standard rules. I accepted this solution because it seems to be valid as well in a nonstandard sense. – Tweakimp Dec 15 '17 at 0:16

Is it:

$\pi$. It is well over 400 years old and pie (sic) can be hot on your tongue if you eat it straight out of the oven.

• No, it is "not so hot on your tongue". And I think you missed the clue in "even longer ago". :p – Tweakimp Dec 7 '17 at 9:53

Is it:

IV? Roman numeral 4, also could be pronounced Ivy, which was used by the Greeks for medicinal purposes. If this is correct, credit to @MeaCulpaNay for pointing me in the right direction.

• No, sorry. I cant really tell you why, its just wrong. Is it really over 400 years old? – Tweakimp Dec 7 '17 at 18:54
• Well the Roman Empire is more than 400 years old, and the Greek empire preceded them, so it is a possible fit for the clues. – Sam Hazleton Dec 7 '17 at 18:57

It could be

Phi ( Φ = 1.618033988749895… ) the golden number / golden ratio

As,

It is re-surfaced during peak of renaissance period, though it was conceptualized and used much earlier by Romans/Greeks. Not sure about the ".... not so hot on tongue" part.

• No, what about the "even longer ago" part? :) – Tweakimp Dec 7 '17 at 13:32

I doubt this is it, but could it be:

Because:

1 followed by 100 0s has been around since well, numbers were created really, but it's only been recently referred to as a Googol, which is pronounced the same as Google, and of course the phrase "Google It" is used in the common vernacular when looking anything up online, so it's always hot on the tongue (or the tip of your tongue as we say in the USA).

• The OP says it is NOT hot on the tongue. Is it not? – Mea Culpa Nay Dec 7 '17 at 18:17
• I take there were people who said it wouldn't be so hot on your tongue. to mean people are surprised by how hot it is on your tongue... – John Eisbrener Dec 7 '17 at 18:19
• Maybe I phrased it wrong, but it really is not hot. – Tweakimp Dec 7 '17 at 18:50
• @Tweakimp Maybe it's a regional thing, but after re-reading it again it still implies to me that the word in question is hot and not the other way around. Sorry I missed the correction to JonMark Perry's answer, but maybe you want to further clarify it in the question? – John Eisbrener Dec 7 '17 at 18:54
• @JohnEisbrener English is just not my motherlanguage. What I mean is: "...people said it was not hot on your tongue." Maybe you can help me phrase it better so it is perfectly clear that I mean to say "not hot". Just provide an edit. :) – Tweakimp Dec 7 '17 at 19:04

Is it:

the number 0 (zero)

Because:

It has been around for over 400 years and it is literally the temperature (in celcius) of ice, which is something cold that you can put in your mouth.

• No, what about the "even longer ago" part? So many people seem to miss this :) – Tweakimp Dec 7 '17 at 19:36
• Welcome to puzzling! You can take the tour and earn a badge. With a riddle, you should carefully check each line to make sure your answer fits them all. – micsthepick Dec 7 '17 at 19:46

Unfortunately, I yet lack the reputation to comment, so I have to put this in as an answer.

There are alternative forms of roman numerals, read https://en.wikipedia.org/wiki/Roman_numerals#Special_values

… I think that Tom is right and the supposed solution is at least very debatable. It would at least be rather obscure, and I could not find any statement in the article you mention that supports its validity.

Explanation:

While there are a lot of variants that may all be considered correct forms of their time instead of just typos, there is not a total freedom in how the letters are arranged. As far as I know, and according with the Wikipedia article, the following basic rules are never broken in any variant:
2) The values of the summands decrease from left to right.
3) There is a subtractive notation as a shorthand, in which a single (!) letter left from a greater letter is considered to be negative and is subtracted from the greater. (I'd also insist that only I, X and C were allowed to be used for subtractive notation, but we don't need that part here.)
While it seems difficult to agree on a single set of historical rules, probably because there isn't one, not adhering to at least these 3 rules above would IMHO break the whole system and introduce a lot of ambiguity. For instance rule 3 (which you make use of) is possible only because of rules 1 and 2, otherwise you'd never know what to subtract. If you ignore 1 or 2, then rule 3 makes no sense.
So, from my understanding, 1449 would be noted as MCDIL.
If you insist that double subtraction is a valid thing, I'd be really curious to see where that has been officially used before, and how exactly (see next point). Not to doubt you, but to learn.
At the very least (and if we assume for the sake of argument that MILD is a valid, unambiguous numeral), it means 1451, not 1449, as you would need to subtract I from L first, and then the result from D.
The "closest" valid numeral to MILD, if I'm right, would be MDIL, meaning 1549. While 1451 would be MCDLI.

Apart from that, as you asked for tips on how to pose the question, so as for the 400

I'd not use 400 but 500 in the hint, as it is at least the closest multiple of 100, which helps more for verifying the answer than 400. The 400 here feels just as arbitrary to me as, say, 39.

and as for the phrasing

I'd not say that the number IS more than 500 years old, as that doesn't make any sense to me with just some random number that could resemble a year past. It would be OK with special numbers like e or π, which have been detected to have a special meaning and thus given a special name at some point in the past. And as you see this is what the solvers were going for first. I'd rather say the number LOOKS to be more than 500 years old.

Anyway, thanks for the puzzle.

Could it be:

Euler’s number: $e=2.718...$

Because:

It was first used in the 1600’s. I don’t have a great answer to “so hot on your tongue”. Unless maybe this could be taken to mean “acidic”. Then $e$ is the base of the natural logarithm so it would not be “hot on your tongue”! And this was where it was first used (by John Napier 1618).

• No, what about the "even longer ago" part? :) – Tweakimp Dec 7 '17 at 13:32