MIT's 6.004 computer architecture course builds this exact 4-bit ripple adder before showing why it doesn't scale: the O(n) carry-propagation delay is precisely why Intel and AMD ALUs switch to carry-lookahead or carry-select adders once bit-width grows to 32 or 64 bits. Understanding ripple-carry's bottleneck is the entry point to understanding every faster adder design in real silicon.