Have you heard of XtraMath? It is an awesome non-profit math site that was started in 2007. Anyone can sign up for free. Awesome right?!
It is an individualized math practice website that requires about five minutes of practice a day (we usually practice 3 times per week). Teachers often sign up their whole class.
We use my ipad for this but you can use pretty much anything that has an Internet connection.
Think of xtramath as digital flash cards with progress reports. It has addition, subtraction, multiplication and division. My daughter is almost done with the addition. I'll have to let her choose a big prize when she finishes.