Here are some useful math links:
EVERYDAY MATH GAMES FOR FIRST GRADE: http://media.emgames.com/emgames/demosite/demolevel1.html
Number Grid Game: http://www.abcya.com/interactive_100_number_chart.htm
Shape Tic Tac Toe Game for two players: http://www.hbschool.com/activity/buzz/buzz.html
Rekenrek game: http://www.ronblond.com/MathGlossary/Division01/Rekenrek/REKENREK/index.html
On-line calculator: http://www.metacalc.com/
Telling time game for two players: http://www.harcourtschool.com/activity/willy/willy.html
Swimming Fish counting game: http://www.primarygames.com/math/fishycount/index.htm
Addition game: http://www.primarygames.com/add_up/question6.htm
Connect the dots (many choices of numbers): http://www.abcya.com/first_grade_computers.htm
Move the clock hands to any time you like: http://www.amblesideprimary.com/ambleweb/mentalmaths/clock.html