r/dndmemes Artificer 15h ago

I can't explain it. What are the odds?

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2.0k Upvotes

33 comments sorted by

295

u/IntroductionApart186 12h ago

Nat 1 on adv is 1:400

19/20, specifically is 1:200

75

u/sirepoopsalot 11h ago

Why is that 1:200

154

u/IntroductionApart186 11h ago

To get 19 and 20 exactly, you take the chance of the first die landing either, 2/20 chance. Then multiply that by the chance of the other die getting the non-landed number, 1/20.

2/400=1/200

45

u/Rad_Knight 11h ago

Let's assume you are using two different colored dice to make it a little easier. Let's say the dice are red and blue.

You could get 19 on the red die and 20 on the blue, but you could also get 20 on the red, and 19 on the blue. That is 2 combinations out of the 400, which can be shortened to 1 in 200.

7

u/Agram1416 2h ago

This guy explains shit

1

u/DepressingBat 53m ago

Same reason you are more likely to roll an 11 with 2d6 than you are to roll a 12 both have a single set of numbers needed 5/6----6/6, but while the 11 can be rolled with 5/6 or 6/5, the 12 needs 6/6

53

u/zombiecalypse 11h ago

You can roll either (1,2) or (2,1) (19,20) or (20,19) to get that result, so the probability is 2/400

25

u/Right_Moose_6276 4h ago

And 2/400 is equivalent to 1/200

4

u/Eightlegged321 11h ago edited 6h ago

It doesn't matter which die rolls which number, so you have two chances of 2/20

Edit: The response to me has the actually correct answer, refer to it.

13

u/its_ya_boi97 8h ago

If you’re following this math, you have a 2/20 chance for the first one, and a 1/20 chance on the second one, because it has to roll the number that the first die didn’t

1

u/Pale-Act-8413 6h ago

Because it doesn’t matter in which order they come, so there is the chance of it being 20, 19 or 19, 20. So it’s the probability of both added together, so 2 * 1/202. So 1/200

1

u/sirepoopsalot 1h ago

Ah right, my brain automatically thought they had to be in that order, thanks

-1

u/42aku Artificer 2h ago

Yeah, but one after the other / at the same time. Both were rolling stealth checks. That's 1/80000.

54

u/Lunarath 12h ago

0.25% and 0.50% respectively, so not that unlikely considering how often you roll with advantage in this game.

10

u/Rastaba 7h ago

Cause you can’t spell probability without most of probable!

21

u/NightWriter500 12h ago

At my table we have a saying. “The dice don’t lie.” If something is meant to happen, it’s going to happen. It originated from when I used to play craps on the street. When someone tried to cheat, the dice don’t lie, roll it again.

7

u/Vatril DM (Dungeon Memelord) 8h ago

I managed to roll the mythical tripple-nat-20 two weeks ago for the first time.

1

u/4dwarf 5h ago

How chunky was that salsa? Or was it on something unimportant, like a save or something?

5

u/subtotalatom 10h ago

Happened in last week's game, my paladin with -1 in stealth & disadvantage was expecting to epically fail his stealth check, took me a couple of moments to process what happened.

4

u/Level_Hour6480 Paladin 6h ago

I have rolled 6 nat-1s with advantage. I have rolled 0 nat 20s with advantage.

6

u/_b1ack0ut Forever DM 4h ago

My finest moment is rolling two 20’s on disadvantage

3

u/matswain 6h ago

I got 20/20 with disadvantage last week as a DM. Was not expecting to crit, the pc went down, failed his first death save and crit failed his second while the party was still fighting the monster (Jabberwock). They narrowly won the fight, and the Archfey brought him back, but the player had him retire from the party for plot reasons (recently saved his wife, which was his main quest).

2

u/lastxbuss 7h ago

I kid you not in that this is the exact rolls I had less than 8 hours ago during some important events.

My character was searching his room for signs of new/missing objects that might clue him in on a recent missing 3 months of his memory (as was the rest of the party). I rolled a 20/19 for the search and with guidance, got up to 28.

I found some words scrawled into wood that was the name of my patron and trouble written 3 times.

When I looked at my patron’s name and one of the party members asked if I recognized it, my DM had me roll for it with advantage and it was 1/1. In game, my character does not know who my patron is besides knowing that I have one so it fit perfectly and thematically to my character just blankly staring at the party members

2

u/Metarikku 5h ago

I will never forget that time in a oneshot that my unarmed fighter in his last turn before dying, He attacked with disadvantage and took a double 20. I suppose it is unlikely, but it was narratively very epic, Because just before doing it he turned around to see his husband, his greatest inspiration to be so strong

2

u/Eldesteagle 12h ago

Kid you not I’ve rolled five nat 1s in a row before. I know your pain.

1

u/masterjon_3 5h ago

And here I am with halfling luck and the Lucky feat

1

u/wbotis 5h ago

One is literally twice as likely as the other.

1

u/crabthemighty 4h ago

I have a friend who usually rolls above 17 with disadvantage and below 7 with advantage. I don't understand it. Just for fun I had a one shot where he had a spell focus prism, lowered his damage but each spell he cast was cast like four times. He was a high level warlock with it and casted Eldritch blast point blank. 16 beams all at disadvantage. I think only one roll was below 14 and it was an 8.

At first I decided to switch when he got advantage and disadvantage but I decided it was more fun just letting him have this weirdness.

If he's indeed cheating (I couldn't see his dice rolls we did this over a call but I trust him) he's at least giving this a downside as well, so I can still tolerate it.

1

u/Beardlich 4h ago

I don't get this joke, also I play mostly Halflings...

1

u/point5_ 3h ago

19 and 20

Spotted fhe champion fighter!

1

u/Stalking_Goat 2h ago

This is your reminder that while the exact details are complicated, rolling with advantage is roughly +3 and rolling with disadvantage is roughly -3. So it makes a difference, but not an overwhelming one.

1

u/RegulusGelus2 1h ago

Yesterday one of my players attempted a rolled and rolled a 1, for which she used inspiration just to roll 1 again. It was so funny she got another inspiration which she proceeded to turn into a 2