# I was thinking about the math behind the 2d6 result ranges for DW.

I was thinking about the math behind the 2d6 result ranges for DW.

I was thinking about the math behind the 2d6 result ranges for DW. I’ve always thought it was really elegant but didn’t know why I thought that. So the nerd in me took over and I ran the % chances for the result ranges for 2d6 – 1 to 2d6 + 3.

It’s actually a lot more interesting than I realized. I highlighted a couple of cool points:

In yellow: You have the exact same chance of rolling a 7-9 when rolling 2d6 + nothing and you do when rolling 2d6 + 2, and it’s fairly high at almost 42%.

In green: You have the exact same chance of rolling a miss as you have of rolling a 10+ when rolling 2d6 + 1. This one interests me a lot because the results are almost 25/50/25%. As an alternate to rolling 2d6 for a project I’m working on, Tom Walker (UK) (it won’t let me tag him) suggested flipping 2 coins to get three results (HH, HT [or TH, obviously], TT) which are exactly 25/50/25% chances. It’s just interesting to me to see that the 2 coins method would most closely match a 2d6 + 1 result (because… it’s cool LOL).

In red: You still have a 16.67% chance (craps!) of rolling a miss when rolling 2d6 + 2.

It’s just something interesting (at least to me) to keep in mind.

## 5 thoughts on “I was thinking about the math behind the 2d6 result ranges for DW.”

1. I wrote a little system where you roll a variable number of dice OR flip coins (1-3 of any type) depending on the complexity of what you’re attempting. All evens (or heads) counts as full success, odds (or tails) count as failure, while a mix counts as partial success (each successful die or coin that is a success means that one element of the action was successful).

2. something i noticed when looking at it is that the 2d6-1 and 2d6+3 odds are inverted (58.34% of 6- @ -1 and 58.34% of 10+ @ +3), as are +nothing and +2

3. Mark Weis, yep, it’s perfectly symmetrical, with the “center point” at 7-9 on 2d6+1… may be why they chose the result ranges they did (6-, 7-9, 10+)

4. I’m glad you were able get in on this Tom (and I STILL can’t tag you). Gotta love G+ lol