Connecting and Collaborating is one of the cons to having an iPad. There is no USB drive, or a slot to put a SD card, in order to move things you create on your iPad to another computer or to share with other people. These apps help you save and share your creations along with giving us ways to collaborate with other people.
Google Drive stores your files but also allows you to work on them with other people. Upload files you create on your iPad and access them on your computer.
Dropbox lets you access any file uploaded into Dropbox from your computer or iPad. Great way to get documents from the iPad to a computer.
Skype is a way to do video calls for free. You can call to conference with other classrooms - update the way you do Pen Pals!
Math K-12 CCS gives you ideas for implementing the CCSS. Also allows you to collaborate and share activities you add into the app.
Common Core Look-Fors helps you integrate the CCSS. It gives you a way to document how and when CCSS are being implemented.
Nearpod enables you to manage the content students see on their device. You can create presentations and assessments that will appear on their devices.
Edmodo is like Facebook for your classroom. Have discussions, inform students & parents. You can share files and photos.
KidBlog! They can create right on the iPad and you can manage and see posts and comments.
Edublogs is another alternative to get kids creating blogs of their learning.
DocAS lets you take notes, annotate PDFs, convert documents to PDFs and share them. Full version is $6.99.
Have you found a good way to collaborate using the iPad?