title: How to calculate size of memory by given a range of address?
body: <p>I have an exercice that I couldn't resolve it,
  I have  3 memory range :</p>
  
  <pre><code>      First @      Last @ 
  </code></pre>
  
  <p>range1:  FD00 0000 to  FDFF FFFF</p>
  
  <p>range2 : D000 0000 to DFFF FFFF</p>
  
  <p>range3 : FA00 0000 to FBFF FFFF</p>
  
  <p>the question is :give the size of the memory for each range (Mega byte)?</p>
  
  <p>what I know is that I should calculate size of the range = last address - first address
  so the result for the first range is : 00FF FFFF .
  Is this right? then what should I do? I have searched on the internet I didn't found an example </p>
  
  <p>Please help</p>