Get Educated - Printing 50 Notes per Sheet

Well, now THAT is pretty interesting!

I never knew what that little letter and number in the upper left of bills was actually for.  I just knew it was there.

I guess this number-letter combo appears on all denominations and not just ones?
Although, according to the video, currently, all notes are in sheets of 32, and ones will be the first to come out on the new sheets of 50.

P.S. This got me interested...when I noticed small letters and numbers in the lower right didn't match those in the upper left. So I found this site, which helped me know what THOSE letters and numbers are for.

http://www.onedollarbill.org/decoding.html