I write my number down incorrectly and can't find it after voting. Straightforward error correction techniques would help identify and compensate for minor err

I write my number down incorrectly and can't find it after voting. Straightforward error correction techniques would help identify and compensate for minor errors and simple adding machine style recipt printers incorporating such logic could be made available within voting booths. Voters who want a recipt would just type the revealed code into the printer.