Great resource for Smartboard-ready demonstrations. Most reousrces are Flash-based so they wont run on an iPAd put they will run via a Smartboard and cover a wide range of math topics.
Sum Dog is a great site with math games that are free to play, either at home or at school. With over 100 numeracy topics, split into 10 levels, most of the games are multi-player, allowing students to play against thousands of peers worldwide. The games are designed to be engaging and fun, helping students enjoy developing their numeracy skills.