title: Subtracting fixed point binary numbers?
body: <p>ello guys,</p>
  
  <p>I know this is really silly but I am a little confused about how to do the following operation by hand:</p>
  
  <p>0.25-0.5? or any similar questions</p>
  
  <p>Also, when it comes to fixed point signed numbers, how do you subtract them?</p>
  
  <p>Say I choose my MSB to be the sign and the 7th bit in an 8 bit number to be 1, while bits 6-0 are the fractional part as shown below:</p>
  
  <p>[SIGN][2^0][2^-1][2^-2][2^-3][2^-4][2^-5][2^-6]</p>
  
  <p>So for example: 01.100000 is 1.5 in decimal. </p>
  
  <p>When aligning the decimal point its easy to add say 1+0.25:</p>
  
  <p>01.000000
  +00.010000
  =01.010000 = 1.25 in decimal </p>
  
  <p>But how would I do 0.25-1? or -0.25-1? </p>
  
  <p>Hope you can help!</p>