What would be the best approach to transcribing QR codes, placed next to examples in a textbook and linking to web pages with homework help? A TN on the general TN page that all QR codes are omitted or local TNs along the lines @.<QR Code URL@.>?
There are no formal rules about QR codes. What I've seen most is the general TN on the TN page that all QR codes are omitted. However, if you can easily "see" the links that they refer you to and it is not the SAME link every time, a more specific TN at each site might be helpful for the reader. Choose and then be consistent.
Yes, each QR Code leads to a different web page with some specific content. Though I'm not sure about their compliance with web accessibility requirements, but again, even if not compliant, these pages might still be helpful with help from others.