Maths Frame is a website from the UK that has some nice materials to use in the classroom. This site offers quite a few games, some of which are free, that provide scaffolding for certain math skills.
I clicked on the resources tab first and checked out a huge list of possible games. The first game I looked at is called Coordinates - reasoning about position and shapes. You are given a choice of four levels. The first two levels limit coordinates to one plane while the second two levels use all four coordinates. The second shape was a rectangle and I had to find the missing coordinate.
If you do not select the proper answer, it just disappears. Only the correct coordinate will work. Then I checked specific math topics such as comparing and ordering numbers. There were two different free games I could have chosen. One was comparing numbers on a number line while the other has the player estimating the position of the number on a number line.
Although many of the games are geared for younger children, there are some free games that could be used by middle school or high school students who need extra work on certain topics. I found a perfect game for my pre-algebra class. They are starting the unit on decimals tomorrow and most of the students are well below grade level with their skills.
Its called Placing Calculations on a Number Line which has students work with either whole numbers or decimals. They either add, subtract, multiply, or divide numbers and select the answer on a number line. I checked out adding decimals and discovered students are given a choice of ten different possibilities to practice. I don't know if it will work on my iPad but it does work on my Mac. I'll know when I try it in my classroom.
Go check it out and see if it works for your students.