Inventory Formula w/two lists

Hello Excel Jedi’s,

I’m hoping somebody can help with what I thought would be an easy solution.  I have a master spreadsheet listing UPC numbers.  I’m able to barcode scan numbers into excel but can’t figure out how it will reference the master spreadsheet to create a count.  

Any idea how I can create a table or formula so when I scan the list of UPC’s in, it references the master list to create a running count?  

Thanks so much!