# d20 System Basics

#### Morrus

##### Well, that was fun
Staff member

[h=3]Dice Notation[/h]
These rules use the following die notations:

[bar]Table: Dice Notaion[/bar]
 d4 d6 d8 d10 d12 d20 d\$ four sided die six sided die eight sided die ten sided die twelve sided die twenty sided die percentile dice (a number between 1 and 100 is generated by rolling two different ten-sided dice. One (designated before rolling) is the tens digit. The other is the ones digit. Two 0s represent 100.)
Die rolls are expressed in the format:

[#] die type [+/- modifiers]

Example: 3d6+2 means: "Roll 3 six sided dice. Add the result of the three dice together. Add 2."

[h=5]Rounding Fractions[/h] In general, if you wind up with a fraction, round down, even if the fraction is one-half or larger.
Exception: Certain rolls, such as damage and hit points, have a minimum of 1.
[h=5]Multiplying[/h] Sometimes a special rule makes you multiply a number or a die roll. As long as you’re applying a single multiplier, multiply the number normally. When two or more multipliers apply, however, combine them into a single multiple, with each extra multiple adding 1 less than its value to the first multiple. Thus, a double (x2) and a double (x2) applied to the same number results in a triple (x3, because 2 + 1 = 3).

[h=5]Basic Task Resolution System[/h] These rules assume a standardized system for determining the success or failure of any given task. That system is:

d20 + Modifiers vs. Target Number

The Modifiers and Target Number are determined by the type of task.

If the result of the d20 roll + the Modifiers equals or exceeds the Target Number, the test s successful. Any other result is a failure.

A "natural 20" on the die roll is not an automatic success. A "natural 1" on the die roll is not an automatic failure, unless the rules state otherwise.

[h=3]DEPARTMENT 7[/h]
Department-7 is a fictional elite organization that the heroes belong to that deals with situations threatening the modern world. Depending on the campaign, Department-7 might have federal authority, or it might be a state or local agency, or perhaps a private institution. In some campaigns, it might have an international scope thanks to ties to the United Nations or some global conglomerate. Department-7 might deal with homeland defense, law enforcement, espionage and intelligence, or counterterrorism. In some games, it might have a charter to investigate paranormal activity or alien incursions or dimensional displacement.

It is our hope that other publishers will use Department-7 as an example in their products, thereby providing a common feel for the game.

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