title: Sum numbers each 80 lines one line awk
body: <p>I have a very large text file that's a vector of numbers, and I would like to add 80 lines together, print the result in a new file, then take the second 81-160 lines, add them up and print the result in the next line of the new file, and so on, until the end of file.  </p>
  
  <p>NOte that the number of lines is not necessarily multiple of 80 so for the last line I'd have to add the remaining lines.</p>
  
  <p>Is it possible to do this fast and in one line using awk, or similar programming language?</p>
  
  <p>Thanks.</p>
  
  <p>Note2: the file looks like this:</p>
  
  <pre><code>3.456
  3.4
  6.788
  9.342
  ... etc ...
  </code></pre>