I have a smart board in my classroom. I found the neatest virtual math manipulative site. We use this all the time to teach regrouping. You can move the manipulative's on the smart board and the kids can use manipulative's at their desks. I love this site. I hope you have a smart board like me and can find this site useful.
It is the national library of virtual manipulative's. http://nlvm.usu.edu/en/nav/vlibray.html