Welcome to GMs Corner. A new curated collection of opinion pieces from our local GMs.
Hello!
Welcome to the first installment of the GM’s Corner here at Dice Dungeons. This will be a section where we discuss GM things; from how to get over your anxiety as a first time GM to tips and tricks even pros can use.
This time, I have been specifically asked to talk about a subject that I am very passionate about, and have only seen discussed in one buried thread in some orphaned forum somewhere:
You are rolling your d100 rolls wrong.
Now, it’s probably not your fault; these things get passed on from GM to player, and then from player to other players… like some sort of transferable disease. Don’t understand what you’re doing wrong? Let me show you.
Ok, First off, I’m talking about rolling a percentile die along with a d10. If you’re rolling an actual d100, well, this discussion isn’t for you. Let’s look at our dice, shall we?
The d10 is a pretty common damage die used in various RPGs, ranging from a d20 system like Dungeons & Dragons to 2d6 systems like those using the Powered by the Apocalypse engine. Let’s go over what each side means when rolling it in this context, shall we?
Now, let’s take a look at the percentile die. This has a very similar numbering scheme to the d10, with one very important distinction: there is an additional 0 after each number. These are used to denote the zeroes, tens, and nineties place.
Now, you might be saying, “Uh, yea. Obviously. This is a dumb article written by a dumb-o”. Well, let’s just reserve that judgement until after this next bit, ok?
So, in order to get a d100 roll without using an enormous golf ball of a die, we roll a percentile die and a d10 and add the result, right?
For instance, this is 37.
And this is 82.
And this is 69. Nice.
But what, I ask you, would you call the following roll?
Every single person I know would call this roll a 50. You’re treating the 0 on the d10 as an actual 0. OK. So, then I ask of you, what is the following roll?
Well, that’s obviously a 7. You have 00 on the percentile, and a 7 on the d10. It can only be a 7. It sure as heck isn’t 107, right? Because that’s outside of the range of the d100 roll, right? Because a d100 roll is from 1-100, right?
Everything I’ve shown you so far is fine.
Or it would be, if it weren’t for one little thing…
You see, you cannot treat both the 0 on a d10 as a zero and the 00 on the percentile die as the ‘zero’s place marker’.
It works for the most part, sure. A 10 would be a 10 and 0 on the percentile and d10. Same works for 20, 30, etc…
But, dear friends, how do you roll a 100 this way?
Most people would say a 00 on the percentile and a 0 on the d10. BUT, given the facts I’ve just carefully laid out, that violates the rules you determine the rest of your rolls by. A 00-0 roll would, technically, be a straight up zero.
Instead of a 1-100 scale, you’ve made yourself a 0-99 scale.
“Oh God, you’re right! How could we have been so stupid? How can we possibly repair this travesty?!” you cry out. Well, I’m benevolent enough a GM that I wouldn’t destroy your world view if I didn’t have a better one to replace it with. And, honestly, it’s pretty simple:
TREAT THE d10 THE SAME WAY YOU’VE ALWAYS TREATED IT.
This way, everything works out perfectly. You can’t roll a zero; a 00-0 roll would be a 10. A 00-1 would be a 1. 90-0 is the coveted 100 roll. Sure, a 40-0 roll being a 50 isn’t immediately obvious, but this is the only internally consistent method I can see here.
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Maybe you don’t want to change. That’s fine; change is hard. But know, fellow GMs and players, that the method you’re using is invalid. You’re changing the rules for different cases.
In a world where consistency in rules and mechanics is required, why too wouldn’t it be required when rolling the dice?
99 comments
I agree with the users saying:
—D&D RAW couldn’t be clearer that 0-00 is meant to be 100 in that system.
—treating 20-0 as 30, 50-0 as 60 etc. feels to me more unintuitive/inconsistent than having 0-00 be the only exception to an otherwise consistent pattern
—Either method produces fair and unambiguous results as long as everyone at the table understands and agrees ahead of time which method will be used.
I also just generally like the feeling of 0-00 being a special case result. It sort of reminds me of the green spaces on a roulette wheel or something.
The system you’re proposing has room for confusion.
Couldn’t you just add 1 to whatever score you roll, or subtract 1 from whatever table you’re referencing?
You still have 100 possible scores in either case. You just need to shift the to roll match the 1-100 scale, or shift the table to match the 0-99 scale. The probabilities don’t change at all.
Yeah, rolling a 50-5 and having it be 56 might feel a little off at first, but it’s a stupid-easy calculation and doing it for every roll feels more consistent and intuitive than adding 10, but only if you roll a zero on the d10 die. A 00-0 should make you feel like a loser and 90-9 should make you feel like a baller.
Just my two cents.
It’s funny when I see comments about “00 & 0=100 is how it’s always been”. That’s the way it’s been since dnd picked it up, but percentile does in ttrpg predates dnd. The original method is 00=0 and 0=10. That’s from a very old game about the battle of Waterloo, where percentiles are the only dice used to determine outcomes of any action or event. Use whichever works best for your group is what I say, but this article depicts the original method.
This isn’t debatable. The rules are clear and in plan English:
“Percentile dice, or d100, work a little differently. You generate a number between 1 and 100 by rolling two different ten-sided dice numbered from 0 to 9. One die (designated before you roll) gives the tens digit, and the other gives the ones digit. If you roll a 7 and a 1, for example, the number rolled is 71. Two 0s represent 100. Some ten-sided dice are numbered in tens (00, 10, 20, and so on), making it easier to distinguish the tens digit from the ones digit. In this case, a roll of 70 and 1 is 71, and 00 and 0 is 100.”
http://dnd.wizards.com/products/tabletop/players-basic-rules
Ok, so, I get the logic of it, but the way most people are doing it doesn’t change the number of possible results and is easier math. Obviously, just as there is no 107 on the combo d100, there is also no 0. So, similarly to how the ace in blackjack can be the high or low, the 00 is as well, depending on what it’s coupled with. So:
00:1-9=1-9
10:0-9=10-19
20:0-9=20-29
etc etc until all that remains is the question of what to do with…
00:0
Which, since there is no 0 score, gets carried around to be the high number: 100. Same chances, still doesn’t leave out any numbers between 1-100, and most of all is easier to read for everyone without hiccups/misreading caused by briefly glancing at results and accidentally thinking a 40 is 30 because that’s what we naturally read 30:0 as.