I taught college pupils to math and basics of cs. I think the "multimedia" materials make things worse in many cases, because people are not enforced to imagine

I taught college pupils to math and basics of cs. I think the "multimedia" materials make things worse in many cases, because people are not enforced to imagine things or just think hard on problems. The mistakes, the way of discovery toward e.g. a formal proof also help them to understand more tougher problems and advanced learning materials and instant solutions on the net take this opportunity away.