These games will develop familiarity with the number system and "landmarks" such as 10s, 100s, and 1,000s.  The games will provide  engaging opportunities to practice computation.  It is best to work on one or two number facts at a time.  When those two facts are mastered, move on to one or two more.  That way, the task is less daunting.

Games to help children learn number facts:

•  Lots of Spots (addition, equivalent value)
• Directions
• Gameboard
• Number of the Day
• Directions
• Addition Tic Tac Toe
• Directions
• Gameboard
• Greatest Number Wins (2 digit)
• Directions
• Hexagon Cookies Gr 2
• Directions
• Double Top It

Online Resources for parents and children: 

• Glossary of Terms
• Digital Math Manipulatives
• General Site
• Word/Numeral Match Activity
• Doubles Game
• Addition Game
• Addition/Subtraction Games
• Addition/Subtraction/Multiplication Games
• Interactive Tangram Puzzles
• Tangram Template
• Telling Time Activity
• Source for Lots of Games