Ask Dr. Math, answers to elementary school level math.
http://mathforum.org/dr.math/drmath.elem.html

Ask Dr. Math, answers to middle school level math.
http://mathforum.org/dr.math/drmath.middle.html

This is a help resource for grade school math.
http://www.teachrkids.com/
http://www.internet4classrooms.com/links_grades_kindergarten_12/
general_math_resources_math_elementary.htm
http://www.allmath.com/
http://www.coolmath4kids.com
http://www.mathleague.com/help/help.htm
http://www.homeschoolmath.net/online/math_games_fun.php

Logical thinking skills.
http://www.syvum.com/iq/

Brain teasers for grades 3 through 8.
http://www.coolmath4kids.com
http://www.mathplayground.com/
http://www.homeschoolmath.net/online/math_games_fun.php

Flashcards for kids at different levels of math.
http://www.aplusmath.com/Flashcards/
http://www.factmonster.com/math/flashcards.html

October 2011 UB/112jw