Practice Math Worksheets on the iPad through Math Pentagon. Though the app is free, you do have to pay for the service. It definitely has a lot of potential.
"CCL4s provides an interface for entering observation data as well as access to all the Content Standards for Mathematics K-12 and the ISTE NETS.S. The collected observation data can be shared via email or with our unique built-in instant meeting. The graphs are very interactive and allow observers to merge different observations to compare and contrast different teachers or the same teacher over time. Using the Timeline feature, observers can track the observed Look-fors through time."
This could be the best $.99 spent on an app. Tools 4 Students includes 25 graphic organizers that can be annotated in the app and then shared via email.
This is a "just-in-time" resource for preK-3rd grade teachers at Central School. These resources are aligned to NETS-T national standards and support the district's goals of technology integration and increased rigor in the classroom.