Run often had BASIC programs that built machine language routines from DATA statements, just a series of numbers. At one point they changed the program so that one of the bytes in each DATA statement was a checksum, and it would tell you if the rest of the line was accurate or not. That helped a lot.
My mom likes to say "I was just having fun, typing in the games and playing them, but you were actually learning something."
That was my first introduction to the notion of checksums and parity bits too. Very practical, in your face, real world consequences kind of impact. Excellent way to learn the concept. I don't miss having to type in all my software by hand, but the sort of forced physical learning and in-your-face impact of syntax and data patterns was really effective and something we should miss.
My mom likes to say "I was just having fun, typing in the games and playing them, but you were actually learning something."