One of the tools we have been using for the "Explore" or "Using Maniuplatives" station has been Evernote. This allows students to document their work as well as explain their thinking. In 3rd grade, students take a picture of their work, and complete a sentence frame to help document their thinking. The process is SO simple, as it supports students' language, and requires NO typing! Here is an example of what one student did:
Here are the instructions our students follow in order to complete their Evernote documentation. Having students tag their work makes it so easy for us to find what they've done on a particular topic.