title: Get the highest number that is divisible by 4 from a total number ( total = 25, I want 24)
body: <p>Say I have an array with 25 elements, I want them in four even groups.  So, I want only the first 24 elements.  But if I wind up with 17, I only want 16, etc etc.</p>
  
  <p>I could foreach them, with modulo, checking for the last one that is divisible by 4.  But, it seems like there would be a smarter way? PHP, por favor.</p>