No question is silly to the honest asker.
1. I believe "Fr numbers" are a catalogue reference, referring to the entry number in A guide book of United States Paper Money by Arthur L. Friedberg. You won't find any way of finding out the Fr number just by looking at the note; you need a copy of the catalogue.
2. I believe the little letters and numbers in the corners of old-style US notes are referred to as "position numbers". They tell yo where on the sheet of uncut banknotes the banknote came from. They are used in fault detection; if they spot an error on a finished note, they can know exactly where to go on the printing plate to look for the problem. This BEP .pdf file shows the position numbers on a $1 note.
1. I believe "Fr numbers" are a catalogue reference, referring to the entry number in A guide book of United States Paper Money by Arthur L. Friedberg. You won't find any way of finding out the Fr number just by looking at the note; you need a copy of the catalogue.
2. I believe the little letters and numbers in the corners of old-style US notes are referred to as "position numbers". They tell yo where on the sheet of uncut banknotes the banknote came from. They are used in fault detection; if they spot an error on a finished note, they can know exactly where to go on the printing plate to look for the problem. This BEP .pdf file shows the position numbers on a $1 note.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis




















