title: Vim search and replace, adding a constant
body: <p>I know this is a long shot, but I have a huge text file and I need to add a given number to other numbers matching some criteria.</p>
  
  <p>Eg.</p>
  
  <pre><code>identifying text 1.1200
  identifying text 1.1400
  </code></pre>
  
  <p>and I'd like to transform this (by adding say 1.15) to</p>
  
  <pre><code>identifying text 2.2700
  identifying text 2.2900
  </code></pre>
  
  <p>Normally I'd do this in Python, but it's on a Windows machine where I can't install too many things. I've got Vim though :)</p>