title: how convert two bytes into one 16-bit number?
body: <p>I understand that 1 byte will hold a number from 0-255. And that a 16-bit number is between 0-65535.</p>
  
  <p>If I'm trying to represent a 16-bit number using two separate 8-bit registers...how do I do that? How does the math work?</p>
  
  <p>Thanks!</p>