Our new addition page has the most detail about adding integers. If you want to know how to add in binary, or you need to learn about "carry" or "overflow", then the addition page will help you.
Assembly hackers need to know how to add numbers using their processor. I added a section for 6502 and 65816 to the addition page, showing basic procedures like how to clc before adc, and how to add 16-bit integers. I forgot to mention the inc instruction, and I forgot to show how adc affects the 65816 processor flags, especially the carry flag and the overflow flag.
Though I forgot to include those things, the addition page remains very detailed. I might want to save time and not write so much detail when I create the subtraction and comparison pages.