(Sample link) White House for Kids http://www.whitehouse.gov/kids/whlife/index.html
(Sample link) National Geographic for Kids http://www.nationalgeographic.com/kids/
Scholastic http://www.scholastic.com
Study Island http://www.studyisland.com
Math Computation http://www.math.com/students/practice/arithmeticpractice.htm
Math Computation http://fen.funbrain.com/cgi-bin/shtml.cgi?A1=../math/index.html
Math Computation http://www.aaamath.com/g3-26a11-add.html
Math Computation http://www.mrsdingman.homestead.com/MathLinks.html
Math Computation http://www.aplusmath.com/Games/