Sometimes the clerk did not read the price accurately. The checkout process was slow. Bar codes were invented to help grocery stores speed up the checkout process.
Now a clerk picks up an item and passes it over a scanner.
The scanner reads the bar code. The store computer searches its memory. It finds the matching bar code. Then it automatically enters the correct price into the cash register.
HOW BAR CODES WORK
A supermarket computer system has in its memory the bar code for each
item in the store. The computer also has in its memory the price of each