All that to say why we needed extra math help, and how we found some wonderful math resources online. Sal Khan has hundreds of excellent, concise math video lessons, all for free at the Khan Academy. He begins with 1+1=2 and goes right through linear algebra. He has even branched out and done some videos on science, history, finance, and test prep. Here is his first place value video and links to his others. (Click the video to start it. Click it again to see it in a larger size on youtube.)
I'm all for teaching math through fun games like UNO, but sometimes you've just got to crank through a worksheet or two to solidify mastery. Softschools.com has help for several subjects including free math worksheets to cover subjects from pre-K through middle school. I like that you can set the minimum and maximum number of digits. Here are the ones I used for place value.