Save the planet by destroying the aliens quickly.  Students need to solve addition problems in order to fire the weapon.  This will surely improve their additions skills and fluency.

In this game, students can compete against each other online to see who can get their jet ski to the end, the quickest by answering addition questions.

This website gives a great example of using the commutative and associative properties of addition using Skittles.  There is a video available that will help demonstrate successful implementation.

Multiplication.com has some really good self-correcting quizzes for math facts.  It allows students to take quizzes with visual hints or without them.  Students can practice math fact fluency for specific math facts that they might be struggling with.  When a student is finished it can even print out an image of how well they did.

Here are other links to 

This is a random three-digit subtraction generator that is

Smartboard friendly, with big buttons. Click the reset values button and the program will generate two 3-digit numbers that students can use to reinforce their ability to subtract.  I use this program to generate subtraction questions and students can use whiteboards to solve the answer.  This can also be used to play games like king of the row or relay races.

This tool is great for teaching young children how to count, add, subtract, and multiply using images on a grid that can go to 144 squares.  There are many variables that teachers can change to make it more entertaining.  Once finished, a teacher can create an image that can then be placed in a presentation, worksheet or on a website.

This is a simple number line make that allows teachers to generate custom number lines  Below are som

Students compete against each other or a computer to see who can win a subtraction tug of war contest.  The quicker the students answer the subtraction problems the harder the tug boat pulls on the rope.

This is a multi-player tug of war addition game.  Players can compete to see who can answer the addition questions quickest and most accurately.