Just saw this in a newspaper today & thought it was interesting. You can tell the genuineness of any €uro note by doing a calculation based on the serial number.
Replace the initial letter on the serial number with the number corresponding to its place in the alphabet ( so A is 1 and Z is 26 ) . Then add this number to each other digit in the serial number in turn. The resulting figure will be a two digit one. Add the individual digits of that figure together. The result should always be 8.
E.G. serial number S15202145752.
S = 19.
add 19+1+5+2+0+2+1+4+5+7+5+2 = 53
add 5+3 = 8 .
Maybe not something you can do at the counter with a queue forming but interesting.
Replace the initial letter on the serial number with the number corresponding to its place in the alphabet ( so A is 1 and Z is 26 ) . Then add this number to each other digit in the serial number in turn. The resulting figure will be a two digit one. Add the individual digits of that figure together. The result should always be 8.
E.G. serial number S15202145752.
S = 19.
add 19+1+5+2+0+2+1+4+5+7+5+2 = 53
add 5+3 = 8 .
Maybe not something you can do at the counter with a queue forming but interesting.