It depends on which view type you’re using in Classwork.com. You can combine multiple files when working in Slide View, but not in Scrolling View.

Can I upload multiple files into a single activity in Slide View?

Yes! While you can only create a new activity from a single PDF, Google Slides, or Google Docs file, Slide View gives you flexibility to add more slides from additional files.

This is a great way to combine multiple PDFs or documents into a single interactive activity. Just use the Create new slide(s) from a file option in the Slide menu to add each file.

Can I upload multiple files into Scrolling View?

Unfortunately, the Scrolling View does not currently allow you to add content from multiple documents.