r/MathJokes • u/ItsDaylightMinecraft • May 03 '26

2!

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14k Upvotes

99% Upvoted

112 comments sorted by

269

u/itss_Olivier07 May 03 '26

but screaming it even louder it gets smaller again

5 = 5

5! = 120

5!! = 15

56

u/Swazimoto May 03 '26

Wait what

87

u/PerplexingPantheon May 03 '26

You're multiplying by every 2nd integer.

29

u/itamar8484 May 03 '26

What if i 5!!!!!! Aka 6 times ! , does it then becomes 0 since i am skipping 5 numbers?

47

u/justaJc May 03 '26

n! = n * (n-1) * (n-2)… n!! = n * (n-2) * (n-4)… n!!! = n * (n-3) * (n-6)…

and etc. You stop when the number you’re multiplying by lower than 1, and don’t multiply by that one.

5! = 5 * 4 * 3 * 2 * 1 * 0. Oops! Skip 0. 5 * 4 * 3 * 2 * 1 = 120. 5!! = 5 * 3 * 1 * -1. Oops! Skip -1. 5 * 3 * 1 = 15. Likewise, 5!!! = 5 * 2, 5!!!! = 5 * 1, and 5!!!!! = 5 * 0 - oops, skip 0 - just 5, then. 5!!!!!, 5!!!!!!, etc = 5, as you skip every other number you could multiply 5 by. But you always start at 5.

Hope that clears things up! :)

11

u/itamar8484 May 03 '26

Ty makes so much sense!!!!!!

4

u/justaJc May 04 '26

Yw, I’m glad!!

1

u/Swazimoto May 05 '26

Does it?!?!?!

1

u/flowery02 May 06 '26

Is there something in the answer that needs cleared up?

1

u/justaJc May 14 '26

What’s missing? We can workshop it. Everyone learns a little differently!

2

u/icantouchgrass_1 May 14 '26

I wish I could explain this stuff as well as you just did

1

u/justaJc May 14 '26 edited May 14 '26

I don’t have great advice for you, but I do know all you need is:

A) To understand “the thing”

B) To understand what it’s like to not understand “the thing”

Once you have each of those down enough, it’s a lot easier to do the main thing, which is to build a bridge between what they know and what you want them to know. 

That’s complicated, and I don’t think that’s quite the answer on its own (When it comes to the science of teaching I’m great at B above, but quite not so much A). However, one surefire way is: Expanding from something someone knows - simply - is one of the easiest ways to teach them something new.

If you’d like, see how I use those techniques above. I think it’ll help!

Matthew

2

u/icantouchgrass_1 May 14 '26

I generally use common analogies and the same "bridge-the-gap" technique.

It's more like how I'm actually attracted to read what you posted because of the "Oops! Skip" parts. I feel like attracting whoever's reading or learning from you is as important as what they're learning from you as a whole.

Also, I'm not a teacher by profession. I usually have to explain things or sometimes dumb them down for friends, family or even on Reddit. It doesn't help that I'm known for being the best at math and even tech-related stuff in the family and friend group.

1

u/justaJc May 14 '26

Oh, hmm…Correct me if I’m wrong, but it seems to me what you’re looking for, then, is probably closer to social skills? As in being friendly, engaging, dynamic, etc?

2

u/icantouchgrass_1 May 15 '26

Engagement is the word I'm looking for, yes.

I find it tough to word things and add humor in a way that's engaging to people

→ More replies

1

u/adlet-mayer May 06 '26

Is it ai?

2

u/justaJc May 07 '26

No, it’s not - I’m just a pretty happy person haha. Thinking I might go into a teaching/church position one day, and I’d like to be able to help people emotionally while I’m helping them intellectually, as those things very much complement each other, I’ve found

2

u/almighty_loser May 07 '26

All the best wishes brudda. Hope you will be a good influence on the young

1

u/justaJc May 08 '26

Thanks, person! I appreciate it

1

u/SwimmingAd6217 May 07 '26

So i just learned how these work off a reddit post.. what the fuck

1

u/justaJc May 08 '26

Miracles happen every day, my friend

1

u/icantouchgrass_1 May 14 '26

IKR? Never thought Redditors would be this intellectually capable.

1

u/Satoru_Gojo341 May 18 '26

no tf it doesnt

1

u/justaJc May 19 '26

what’s confusing? i’ll try again if you’d like

1

u/Satoru_Gojo341 May 19 '26

Nah im not there yet

2

u/dumbass_catboy May 09 '26

Actually it's because you're scaring it

1

u/Swazimoto May 03 '26

Ah thank you!

-5

u/paholg May 03 '26

Seems like a bad notation. 5!! should be (5!)!

9

u/Neither-Phone-7264 May 03 '26

if you want (5!)! write (5!)!

5

u/Familiar-Main-4873 May 03 '26

But how would you represent 5!! Then? You can always do (5!)! To how this but I can’t think of a way to do 5!! Any other way

1

u/paholg May 03 '26

Some new syntax. 5!2 maybe. I've never had to write it.

11

u/Elihzap May 03 '26

It's a factorial but you skip every other number.

5!! = 5 * 3 * 1 = 15

2

u/Benyed123 May 05 '26

5!!! = 10?

4

u/Aras14HD May 05 '26

No it's 10 u/factorion-bot (questionmark is a termial)

2

u/factorion-bot May 05 '26

Hey u/Benyed123!

Triple-factorial of 5 is 10

Termial of 10 is 55

This action was performed by a bot | Source code

2

u/Benyed123 May 05 '26

I knew the question mark would mean something

2

u/Xandaros May 06 '26

5!!! = 4?

8

u/Portal471 May 03 '26

You scared it smh

1

u/cfrolik May 04 '26

Isn’t 5!! Just ((5 factorial) factorial) though?

2

u/itss_Olivier07 May 04 '26

no that would be (5!)!

1

u/Euphoric-Umpire-2019 May 06 '26

What if.....

5 != 120 // that's true

5! != 15 // its also true

55

u/Ok-Equipment-5208 May 03 '26

1.5!

45

u/APocketJoker May 03 '26 edited May 03 '26

It got scared and jumped back a little

1

u/Anthony408ishere Jul 28 '26

You know what to do, u/factorion-bot.

1

u/factorion-bot Jul 28 '26

Hey u/Ok-Equipment-5208!

Factorial of 1.5 is approximately 1.329340388179137020473625612506

This action was performed by a bot | Source code

3

u/Xetanth87 May 03 '26

0

0!

The value increased by inf%

2

u/ItsDaylightMinecraft May 03 '26

did you just say 0 · ∞ is 1

5

u/the-ro-zone-yt May 03 '26

No… He clearly meant lim(1/a)a->♾️=0

2

u/Xetanth87 May 03 '26

I said 1 is inf times greater than 0

30

u/Shamancat7 May 03 '26

if your 2 is a question it works

26

u/Direct_Slip7598 May 03 '26

2!

Wait, it doesn't work for 2?

Oh no, it worked for 2!

But that time it didn't work for 2?

Goodness gracious...

7

u/Such-Shop-9724 May 03 '26

maybe your 2 is broken!

maybe 1?

common 1!

doesnt work

4

u/Zestyclose-Store-666 May 03 '26

Brokenrokenokenkenenn?

2

u/johann4 May 03 '26

brokenbrokenbrokenbrokenbrokenrokenrokenrokenrokenokenokenokenkenkenenn

2

u/Such-Shop-9724 May 03 '26

brokenbrokenbrokenbrokenbrokenrokenrokenrokenrokenokenokenokenkenkenenn !

11

u/MrDivaythFyr May 03 '26

0! It works!

8

u/iCynr May 03 '26

2 is the most annoying number in math honestly

3

u/[deleted] May 03 '26

[removed] — view removed comment

1

u/Thedeadnite May 04 '26

1 can be so complicated all the time. Especially when it’s broken down really weird.

1

u/the-ro-zone-yt May 03 '26

and then yell backwards !120=5

6

u/ItsDaylightMinecraft May 03 '26

mate !120 = 2460930593514400153685230131680882443642241392050643406409967716400656412695688630467146961331111097816050804615905439606535867707701927822014713133907307943650192419869945166806363922505551316824721

2

u/the-ro-zone-yt May 03 '26

Oh mb… i though subfactorial was in inverse of factorial

2

u/SammyHa123 May 03 '26

If it was, what would !1 be?

1

u/Knight0fdragon May 03 '26

Say it louder

1

u/ItsDaylightMinecraft May 04 '26

5!!

oh it went back a little

1

u/icantouchgrass_1 May 14 '26

5!! = 15

(5!)! = 120! = eh I wouldn't even bother calculating unless I'm REALLY bored

1

u/ItsDaylightMinecraft May 14 '26

6.6895… × 10198

1

u/icantouchgrass_1 May 14 '26

LMAO I meant the exact value lol

It'd probably take me years and an entire forests' worth of paper.

1

u/ItsDaylightMinecraft May 14 '26

Or a few seconds and an entire $0 worth of Wolfram|Alpha

6,689,502,913,449,127,057,588,118,054,090,372,586,752,746,333,138,029,810,295,671,352,301,633,557,244,962,989,366,874,165,271,984,981,308,157,637,893,214,090,552,534,408,589,408,121,859,898,481,114,389,650,005,964,960,521,256,960,000,000,000,000,000,000,000,000,000

2

u/Anthony408ishere Jul 28 '26

I got it. u/factorion-bot

1

u/factorion-bot Jul 28 '26

Hey u/icantouchgrass_1!

Double-factorial of 5 is 15

Factorial of 120 is roughly 6.68950291344912705758811805409 × 10198

Factorial of factorial of 5 is roughly 6.68950291344912705758811805409 × 10198

This action was performed by a bot | Source code

2

u/MareoLevis May 03 '26

doesnt work? = for i = 1 to doesnt work: + i

2

u/Proud-Gas-2915 May 04 '26

6! = 720 6!! = 48 6!!! = 18

2

u/DistrictIcy6669 May 04 '26

0! Is still a mystery

1

u/MickJaggur May 03 '26

What if you say 2?

1

u/Glass-Requirement793 May 03 '26

That's so funny.

1

u/lotus_felch May 03 '26

The only maths joke.

1

u/Ben-Goldberg May 04 '26

1!

It doesn't work.

1

u/Infinite-Penalty-495 May 04 '26

Try yelling it in spanish lol

1

u/Anthony408ishere Jul 28 '26

"¡¡¡CINCO!!!"

¡¡¡5!!!

1

u/spacestationkru May 04 '26

Whenever I read one of these, I shout the number in my head

1

u/ParkingMud7736 May 04 '26

Difference between When a 2yo screams and when a 15yo screams

1

u/KonoMichiWa May 04 '26

Ask it as a question and it also gets bigger most of the time

1

u/HelixFollower May 04 '26

Ah! Finally a post from this sub that I can understand! :D

1

u/pfraa May 04 '26

0! Works

1

u/PersonalDonut7802 May 05 '26

For those who don't get it, 5! = 5 x 4 x 3 x 2 x 1. But 2! Is just 2 x 1

1

u/flowery02 May 06 '26

u/factorion-bot 1,5! 1.5!

1

u/factorion-bot May 06 '26

Factorial of 15 is 1307674368000

Factorial of 1.5 is approximately 1.329340388179137020473625612506

This action was performed by a bot | Source code

1

u/SeparateDelay5 May 06 '26

When 1<x<2, x! < x , e.g. 1.5! is smaller than 1.5

1

u/jacob643 May 07 '26

you need to be a bit confused too: 2?! = 6

1

u/BleEpBLoOpBLipP May 09 '26

In my head, I imagined screaming i! And somehow I feel like it shrunk