Math Games at Sheppard Software to practice addition, subtraction, multiplication, and division facts

Arcademic Skill Builders - Website with fun, arcade-type games to practice the four basic operations. Both single- and multi-user games.

Decimals

Mr. Nussbaum's Decimal Games

Decimals at Sheppard Software

Decimal games at Gamequarium

Decimal help & tutorials

Decimal Games

Online decimal games at www.free-training-tutorial.com

Decimal math games at math-play.com

Decimal Squares Interactive Games

More Resources & Games

Online games for the four operations and order of operations - Many of these games practice mental math and logical thinking.

A list of games and resources online for place value, even and odd numbers, Roman numerals, large numbers, and rounding

Mental Math Wikibook - Explains with examples lots of common mental math techniques and strategies, for addition, subtraction, multiplication, and division.