CoolMath was started in 1997 to make math enjoyable for people who thought it couldn't be fun. Offers "math for ages 13-100" -- explanations that are easy to grasp on topics like algebra, pre-calculus and more. (I started my career as a math teacher, so it's a great pleasure for me to help people finally understand -- and even enjoy! -- doing math.) Sister sites: CoolMathKids | CoolMathGames.