title: Sum the results of looking up multiple reference values
body: <p>I am seeking a formula to replace my current method of adding another vlookup to my formula string each time another week passes (the current formulas in the cells in column D).  i.e - I would like it to look through my header row (Row 2) for the referenced weeks and find each one of them in my lookup table (FTE_Lookup) to sum all of the corresponding possible hours for those weeks.  I read a couple threads on Sumproduct for multiple vlookups, but it doesn't quite match my situation.  Below is a a link to my dummied-down spreadsheet for an example.  The data in Row 2; Column D; and the FTE_Lookup table are of interest to this problem:</p>
  
  <p><a href="https://drive.google.com/a/vt.edu/file/d/0B7LOhGW3xbKgbGUxS2x1anNfV00/view?usp=sharing" rel="nofollow noreferrer">https://drive.google.com/a/vt.edu/file/d/0B7LOhGW3xbKgbGUxS2x1anNfV00/view?usp=sharing</a></p>
  
  <p><a href="https://i.stack.imgur.com/CT9u4.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/CT9u4.jpg" alt="Vlookup Image"></a></p>
  
  <p>Thank you in advance.</p>