As I'm studying a Reed-Solomon Codes implementation... I think its useful to discuss the concepts of CRCs & Hamming Codes, since Reed-Solomon appears to refine these ideas! I'll discuss CRCs today.
CRCs can detect most accidental transmission-errors in a digital message.
Mathematicans reason about them as "finite-field polynomial division" to determine how effective they are at this task.
For each bit of the message, shift into the CRC. If the outgoing bit's 1, invert certain bits of the CRC.