title: Subtract value to multiple rows
body: <p>Well I am stuck at a point where I need to distribute a value across multiple rows. Since I do not know the specific term, I would put it in the form of example below for better understanding:</p>
  
  <p>Assuming the value of x to be 20, I need to distribute/subtract it to rows in descending order.</p>
  
  <p>TABLE:</p>
  
  <pre><code>ID        Value1 
  1          6             
  2          5
  3          4
  4          3
  5          9
  </code></pre>
  
  <p>Result should look like: (x=20)</p>
  
  <pre><code>ID        Value1     Answer
  1          6           14    
  2          5           9
  3          4           5
  4          3           2
  5          9           0
  </code></pre>
  
  <p>Can anyone just give me an idea how I could go with this? </p>