One of the first things a new Dungeons & Dragons player may puzzle over is the weird dice used in the game. Basic D&D uses six polyhedral dice, with four, six, eight, 10, 12 and 20 faces. These dice are the lifeblood of D&D's game mechanics; they're what you use to figure out if what you're trying to do works, or if it doesn't.
In D&D shorthand, the dice are known by a lowercase "d" followed by the die's total number of sides, so a 20-sided die (an icosahedron) is a d20. This shorthand also tells you the number of times the die needs to be rolled: 2d8 would mean you need to roll the eight-sided die twice (or roll two eight-sided dice) and then add the numbers. In this way, your eight-sided die just became a 16-sided die.
When you roll, you and your DM will be comparing your result to a number found in one of the game's manuals. That comparison will determine your action's outcome: In other words, you can boil all your in-game actions down to numbers. For example, if you're playing a fighter and you swing a battle axe at a wandering ghoul, you'll roll the dice to see if you connect. Since ghouls have an armor class of 14 (which, remember, is how hard it is to hit a character), you'll have to roll a 14 or higher on a 20-sided die (d20) [source: Carton]. If the die roll produces a hit, you'll roll again to see how much damage you inflicted.
The beauty of Dungeons & Dragons is that draped on top of this skeleton of tables and numbers is the flesh and meat of the game, created by the players' imaginations. While an action's outcome boils down to the comparison of two numbers, it's up to you to decide what that action will be. Along the way, you can become engrossed in the game by seeing the action in your mind's eye.
Read on to find out who's responsible for setting up all that action.