Timmy's reviewing fractions today, so I decided to take a quick look at what free interactive games/resources I will find on the Net.  Still haven't gone through everything on my Google results, but I used this one site right away instead of having Timmy do pencil & paper exercises.  Here's the URL:

nlvm.usu.edu/en/nav/frames_asid_103_g_1_t_1.html

It was pretty neat & straightforward, very intuitive, so Tim took to this like fish to water.  He ended up doing many more exercises than he would have on paper.  He seemed tired of writing so I gave him this option.

You might also want to explore the home of this website too.  It's got lots of good stuff, virtual manipulatives for math, such as a number line, etc.  Happy surfing!