2d10

A 2d10 is a type of dice roll in tabletop role-playing games and other probability exercises. It signifies the rolling of two ten-sided dice and summing their results. A standard ten-sided die is numbered from 1 to 10. When two such dice are rolled, the minimum possible sum is 1 + 1 = 2, and the maximum possible sum is 10 + 10 = 20.

The distribution of results from a 2d10 roll is not uniform. Unlike rolling two six-sided dice where the most frequent result is 7, a 2d10 roll has a bell-shaped distribution. The most probable outcome is 11, with results clustering around this value and becoming less likely as they approach the minimum (2) or maximum (20). This shape is characteristic of sums of multiple dice.

The 2d10 mechanic is often used when a wider range of results is desired compared to a single die, but with a more centralized probability curve than, for example, 3d6. It can provide a good balance between randomness and predictability for game mechanics. Some games might use one die as a tens digit and the other as a units digit, creating a roll of 1-100 (often referred to as a percentile roll or d%). However, the context of "2d10" typically implies summing the faces of two distinct ten-sided dice.