Calculation Nation is a website maintained by the National Council of Teachers of Mathematics that is filled with various educational, mathematical games. These games are flash based so are only able to be used on computers or devices that are flash enabled. They do not work on my iPad.
The reason I found this site is I was looking for a game or two that would help my students become more fluent in determining transformations so I did a web search. The search took me to this location for the flip slide game. The student enters the transformations using a series of arrows to show direction and numbers to show how many squares the triangles should be moved so the green triangle is where the blue triangle is.
It takes some thought and it is rather fun. In addition to this game, there are 12 more games designed to help the student acquire mathematical skills. The nice thing about this website is that you may go in as a guest so you end up playing the computer but if you sign up, you can play other people.
I enjoyed exploring EQ of Attack or a mathematical version of battleship where you calculate the line of firing so you hit as many things as you can with the bombs trajectory. It came with all the noise one would expect from a sea battle. Then I tried slam ball which is a game where you bounce balls off the side of the enclosure and try to go through point balls to gain points. It takes a little while to get the hang of it but it requires thought to determine if you want to shoot up or down.
Dig it has students choose a fraction and then show on a number line where the location is. There is a shovel that will dig for gems at the location you designate on the number line. If you are right, then the shovel digs, if not you loose a turn. The final game I played was Ker-splash where balls drop down this toy and the terms it hits end up on that player's side While the other player is rolling, you combine like terms in the combination area so you free space for more balls. It is a bit faster paced than the other games but I enjoyed it because of that. It gives great practice on combining terms.
I wish it would work on my iPads. There are some downloadable apps for tablets but I need to check them out. In the meantime, have fun with Calculation Nation.