CoolMath4Kids-Many math activites but beware, several are more 
difficult than you might think at first glance!
http://www.coolmath4kids.com/

Drop the correct amount of money into the cup to practice coin values.
http://www.toonuniversity.com/flash.asp?err=569&engine=

Coin vault game is a fast paced game where students must add coins to 
match.
http://www.tvokids.com/framesets/play.html?game=161&

Math Playground-Word games and logic games-most activities are geared 
to the older elementary students.
http://www.mathplayground.com/

Practice Multiplication Facts.
http://www.quia.com/mc/8367.html

Math Baseball from Funbrain
http://www.funbrain.com/math/index.html

Defeat the Math Monster
http://www.mrnussbaum.com/monster.htm

Tackle Math Football
http://www.mrnussbaum.com/tackled.htm

Scottie Nickel's Change Maker Activity
http://www.mrnussbaum.com/scottienickel.htm

Bedtime Bandits Time Activity
http://www.mrnussbaum.com/bedtime.htm

Clockworks Testing Time
http://www.mrnussbaum.com/clockworks.htm

A+ Math Activities-Addition, Subtraction, Multiplication and some 
Division
http://www.aplusmath.com/Games/index.html

5th Grade Math Textbook Extra Activities
http://www.eduplace.com/kids/mw/g_5.html

4th Grade Math Textbook Extra Activities
http://www.eduplace.com/kids/mw/g_4.html

3rd Grade Math Textbook Extra Activities
http://www.eduplace.com/kids/mw/g_3.html

2nd Grade Math Textbook Extra Activities
http://www.eduplace.com/kids/mw/g_2.html

1st Grade Math Textbook Extra Activities
http://www.eduplace.com/kids/mw/g_1.html

Mr. Nussbaum's Cash Out-You are the cashier at this store and must 
give the customer change for a purchase.  Three levels of difficulty.
http://www.mrnussbaum.com/cashd.htm

Halloween Math Activities for Grades 1 and 2 (some reading involved.)
http://www.apples4theteacher.com/holidays/halloween/math-games/index.html#

Dojo.  Practice your math facts.  Choose your activity then begin at 
level 1.
http://www.iknowthat.com/com/L3?Area=Dojo

Funbrain Math Arcade-Travel along the game board after you have 
chosen your grade level and see how far you go!
http://www.funbrain.com/brain/MathBrain/MathBrain.html

Jan Brett's Sea Shell Rounding Activity
http://www.janbrett.com/piggybacks/rounding.htm#quiz

Place Value Pirates for 4th Grade!
http://www.mrnussbaum.com/placevaluepirates1.htm

CyberChase from PBS Graphing Game (2nd Grade)
http://pbskids.org/cyberchase/games/bargraphs/bargraphs.html

BBC site for Graphing and Pattern activity. (2nd grade)
http://www.bbc.co.uk/schools/ks2bitesize/maths/activities/interpretingdata.shtml

Create your own graph!  (good for 2nd grade)
http://www.amblesideprimary.com/ambleweb/mentalmaths/grapher.html

BBC Number Math Activities-includes addition, subtraction, number 
patterns, multiplication, fractions, and even decimals.  The BBC has lots of 
great activities!!
http://www.bbc.co.uk/schools/ks2bitesize/maths/number.shtml

Math Magician.  Practice your math facts.  Good for flash-card like 
experience.
http://www.oswego.org/ocsd-web/games/Mathmagician/cathymath.html

Reading Rainbow Hidden Picture Addition and Subtraction Activity
http://pbskids.org/readingrainbow/games/hidden_picture.html

Sum Sense Single Digit Subtraction Activity
http://www.oswego.org/ocsd-web/games/SumSense/sumsub.html

Level 1 Speed Grid Subtraction Activity
http://www.oswego.org/ocsd-web/games/SpeedGrid/Subtraction/urikasub1res.html

Level 2 Speed Grid Subtraction Activity
http://www.oswego.org/ocsd-web/games/SpeedGrid/Subtraction/urikasub2res.html

Number Sense from CyberChase
http://pbskids.org/cyberchase/games/numbersense/index.html

CatchTen
http://www.learningbox.com/Base10/CatchTen.html

Multiplication.com-Many choices to practice multiplication.  Some may 
need to be installed, some are on different web sites.
http://www.multiplication.com/interactive_games.htm

BBC KS1 Bitesize Number Activities including Time and Money.
http://www.bbc.co.uk/schools/ks1bitesize/numeracy/