I TA a few first year engineering classes, and I've come across a handful of students who have had a great deal of difficulty with basic high school level algebra questions. I was in my office this past semester at McMaster, and one visibly upset student came to me complaining about the grade he received on his test. I never even saw this guy during tutorials, but anyway I thought I'd address his concerns to the best of my abilities. His complaint had to do with a question involving integration by parts and substitution. I looked at the solution he put down on the test to that integration problem, and he basically just differentiated the original function, so I was a little perplexed as to why he was upset over his grade. When I started to go over the proper solution with him, he pointed to the integration symbol and stated "what's that?" lol.