My last year high school math class had this approach, and it was a regular math course taken by every student. Same thing at university, in a CS degree. Fresh

My last year high school math class had this approach, and it was a regular math course taken by every student. Same thing at university, in a CS degree. Freshman Calculus taught at a level somewhere between Spivak and Rudin. In fact, both books where on the official course bibliography. All this took place in a fairly big EU country, ~10 years ago.