title: Why are binary numbers almost always grouped in 4 bits?
body: <p>I'm learning ARM so going back to basics with binary/hex arithmetic and it got me thinking about how binary numbers are usually presented in groups of 4, e.g.</p>
  <p>1111 1110 1101 1100</p>
  <p>Is there a particular reason why it's done this way? Seeing as we normally describe memory in terms of bits/bytes/megabytes etc I'd have thought they'd be better grouped by 8?</p>