Another suggestion for fractions is to use fraction stacks. These may already be in your classroom. Basically, they are stackable cubes that represent fractions in four different ways. One side has a typical fraction (1/2), another side has the decimal (0.5), the next has the percentage (50%), and the fourth may have a fraction over one hundred (50/100). This should help with that tricky converting between the rational numbers.
Finally, here is a webpage that i think will work interactively with SMARTboards or whiteboards (don't actually have one to try it out, so i can only presume it works--please leave a comment if you try it and it does or doesn't work).
Like many things on the internet, you can do this on a regular computer, as a whiteboard isn't entirely necessary to use it.