As others have stated, it's mostly issues with the Math and the lack of preparation that most US public high schoolers get in Calculus. I started Engineering (

As others have stated, it's mostly issues with the Math and the lack of preparation that most US public high schoolers get in Calculus. I started Engineering (CS Degree) in Boulder, CO with a guy that came in study Electrical Engineering. He was good with circuit boards and the mechanics involved in electrical parts so EE seemed like a natural fit for him. I went to an International Baccalaureate program in HS and studied Calculus pretty extensively in my 11th and 12th grades. My friend went to a small HS outside of Colorado Springs and never went past Algebra 2. Engineering Calculus 101 showed me the value of my high school math curriculum. I didn't find it too difficult, as it was mostly a review for me. But it destroyed my friend completely. I remember watching his eyes glaze over as he struggled to keep up even in the early sessions. When we all got together to do the homework he was struggling to understand even the basics of Calculus. On his first exam, he scored a 15%. At the professor's office hours, he was told nobody from his HS had passed Calc 101 in the past 5 years. He was advised to switch to B-school and that's where he ended up getting his degree.