Its 1/6 to roll a 7 with two 6-sided dice. You can get weighted dice that make it more likely to land on a certain number.
Does having one weighted dice change the odds at all? My gut says no but reality is a tricky bitch and I’m convinced im wrong somehow.
You’re marginally less likely to roll a 7 with a single weighted die.
My reasoning: if you use your weighted die, whoever you’re gambling against might figure it out. Now they’re pissed, they’re gonna give you the beat down. But you’re packing, and OH SHIT YOU DIDN’T MEAN TO HIT HIM IN THE HEAD YOU WERE AIMING FOR HIS LEG SHIT SHIT and now you’re serving jail time for manslaughter and dice aren’t allowed in jail, thus you won’t be able to roll any 7s for a while.
Don’t worry, there are dice in (at least some) prisons, every cell block had at least one D&D group going with 4-6 people, and they used dice.
Source: Was a prison guard in the ARMY for 4 years at Fort Lewis.
Ah, so the chance of rolling a 7 changes to 1/20?
If you’re rolling D20s, but there are also D4s, D6s, D8s, D10s, D12s, and a D10 Percentage die for 5e, and some spells require multiple of the same dice, so rolling 6d6 is a very real scenario, so you can have plenty of dice to use to find variations to get to 7 with different sided dice.
That just sounds confusing. You’re putting me off murder now.
Once again, D&D improves society.