equation for armor in FPS

[shogunboy]

Is there a equation based on how much an enemy takes away your health with armor? I need this equation for a game board that I am doing for math, and it's going to be similar to D&D (dungeons and dragons). This game is sci-fi, and I just want to know the equation of armor.All I need is just base, because it's hard to tell, I mean I would love the Quake 4 armor equation if you know it please and thank you.

 

[Human1]

Sure there is, but it's different for each game. Just make your own up or something. Can't be too hard.

 

[Guest]

Usually you take your armor rating and the attacker must exclude this from his 1W20 attack roll...

 

[shogunboy]

Thank You for the base equation. You people are really helpful, even for small things like this.