View Full Version : Rolling d20 without a d20

10-16-2014, 11:55 AM
I was traveling recently, and asked myself, "how can I roll dice when I have no dice or no place to roll them?" Case in point: being in a car makes for a horrible gaming table, but a captive audience.

Wanting to go one step further than paper-rock-scissors, I came up with this:

1. GM and player pick any number from 1 to 20.
2. Player announces number, and GM adds it to his number.
3. The result is a d20 roll, unless it's over 20. Then subtract 20 to get result.

For example:

GM selection

Player selection











Does this provide even odds for any number, 1-20? (Assuming the two number selections are random enough!)

Can the same be done with other "dice?"

10-16-2014, 01:03 PM
Interesting. I'm not sure how to even start considering the "odds" on this type of thing. I suspect anything deliberately generated is likely, at least more likely than chance, to have at least slight bias, both on the part of the GM and Players, though I don't know if there is often enough different types of bias between people to make it negligible.

I thought originally of colors, like "pick your favorite color" but I believe some colors are overall just more likely to be chosen, and I suspect some numbers may be "naturally" more likely to be picked than others (though I have no proof), making at the very least, a certain range of numbers more likely than others.

To me you'd be ahead to use something simpler but with a bit more setup, like the random number table from the Lone Wolf adventure game books, where numbers from 1-20 are placed randomly in a grid table, and you close your eyes and probably have someone rotate the table a few times, and then you drop your finger or a pencil and your "roll" is there you indicate.

10-16-2014, 03:54 PM
Dice rolling app on you phone.

Stop watch function, hundredths of a second. Stop, divide by what you need to for the die you need.

Or, carry dice like I do.