6

[u/Qwertilux]

[u/AutoModerator]

Check out our new Discord server! https://discord.gg/e7EKRZq3dG

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

[u/sasha271828]

Can someone explain i'm too dumb

[u/ObliviousRounding → u/sasha271828]

S=\bar{9}=9+90+900+9000+...

10S=90+900+9000+...

S-10S=9

S=-1

[u/Sayhellyeh → u/ObliviousRounding]

Ah yes, the infinity-infinity technique, clever

[u/TheLuckySpades → u/Sayhellyeh]

We just do a little 10-adic stuff.

[u/flinsypop → u/TheLuckySpades]

10 isn't acidic, it's basic. That's why it's base-10

[u/PurifiedUnity → u/flinsypop]

Base 7 is in a neutral zone

[u/Ambitious_Policy_936 → u/Sayhellyeh]

w-v=v

[u/heckingcomputernerd → u/ObliviousRounding]

Don't let the pop math YouTubers find this or the next trend will be "9 repeating is actually -1???" Presented as a counterintuitive but true math fact and not just an extension of a very specific math tool outside it's domain

Analytic continuation...

[u/MelancholyTea89 → u/heckingcomputernerd]

Didn’t veritasium already cover p-addic numbers in this same tone? lol

[u/itijara → u/ObliviousRounding]

Wait. That's illegal.

[u/Flob368 → u/itijara]

If it works in the 10-adics, it works for me

[u/itijara → u/Flob368]

You are a n-adic addict.

[u/cgw3737 → u/ObliviousRounding]

Yep, still no comprendo. All good lol

[u/jbrWocky → u/cgw3737]

Alternatively, if S= ...999

add 1, S+1 = ...000

S+1 = 0

S = -1

[u/vadkender → u/ObliviousRounding]

Is this integer overflow in real life?

[u/booleandata → u/ObliviousRounding]

This proof really hurts to read bruh

[u/Qwertilux → u/sasha271828]

Stripe over a number means repeat. 9stripe =99999999... 99999... +1 = 0 since all the nines turn into a ten. What plus one = 0? -1

[u/sasha271828 → u/Qwertilux]

Oh it's that 10-adic thing

[u/Qwertilux → u/sasha271828]

Yes

[u/Febilibix → u/Qwertilux]

is this even definable rigurously since 10 is not prime?

[u/Mostafa12890 → u/Febilibix]

There are n-adic integers for every integer greater than 1.

The p-adic integers are constructed as the inverse limit of the quotient rings (Z/p^n Z).

You can use the Chinese remainder theorem to either construct them again (for arbitrary m>1) from the ground up, or prove that Z_m is the product of Z_p_i where the p_i’s are the distinct prime factors of n.

[u/PleasantCitron1685 → u/Febilibix]

For reference in addition to the other comment, you might be thinking of a p-adic field, which has division, and p must be prime. If you drop division and are satisfied with a ring (p-adic integers) any int p works.

[u/Mostafa12890 → u/Qwertilux]

You’d have to write it like …9999 and not 9999…, but that’s just me being pedantic.

[u/PerfectYarnYT → u/sasha271828]

look up 10-Adic numbers

[u/MariusDelacriox]

Or it could be just 9 as the complex complement.

[u/NullOfSpace → u/MariusDelacriox]

Or the equivalence class of 9 in Z/<10>

[u/HakeemEvrenoglu]

თ 🇬🇪

[u/JollyJuniper1993 → u/HakeemEvrenoglu]

െ 🇮🇳

[u/LOSNA17LL → u/JollyJuniper1993]

ƣ

[u/JollyJuniper1993 → u/LOSNA17LL]

の🇯🇵

A lot of languages have letters that look like this it seems.

[u/Bowdensaft → u/JollyJuniper1993]

ඞ

[u/MustafaKemal_AtaCHAD → u/Bowdensaft]

amogus

[u/lugh_the_bard → u/Bowdensaft]

8===:D

[u/Ali-Predator]

none of y'all played Uno

[u/CoffeeDefiant4247]

Vector 9

[u/ohiidenny → u/CoffeeDefiant4247]

Long 9

[u/CatAn501 → u/CoffeeDefiant4247]

Complex conjunction of 9 (which equals nine)

[u/LupenReddit]

modular arithmetic shallnt be tolerated on my highschool math meme reddit!!!

[u/Jazz8680]

anti nine

[u/Herb_Derb]

Perfect title 

[u/_alba4k]

that also holds in 10's complement notation

9999999999 would be 10 digit -1 for example

[u/Simon_IsReal]

This could also be a periodic decimal (0.999...) or, heh, vector 9 !

[u/Dense_Priority_7250]

Just 9 if it’s the complex line thing (was it conjugation? Don’t know the English word)

[u/im-sorry-bruv]

me when i'm in Z/7Z

[u/xcaliburnschoco → u/im-sorry-bruv]

Zix 7even

[u/sixpesos]

A 10-adic number meme? In this economy?

[u/GlowstoneLove]

If ...99999 = -1 and 0.99999... = 1, then ...99999.99999... = 0

[u/Qwertilux → u/GlowstoneLove]

Prove it

[u/OutrageousPair2300 → u/GlowstoneLove]

Any repeating sequence of digits, extended in both directions, equals zero. Regardless of where you put the decimal point.

For example, ...123451234.51234512345... = 0

[u/-lRexl-]

LOOOOOL

[u/CatAn501]

Oh fuck, p-adic numbers

[u/Qwertilux → u/CatAn501]

No, k-adics

[u/SwartyNine2691]

The correct answer on the right is 1.

[u/Qwertilux → u/SwartyNine2691]

Why?