check digit in next number

Hi, guys I am learning enterprise one 8.9 ver. I wanted to know what is check digit check box for while creating next number? Unable to understand much from the given help.

a check digit is an extra number added to the end of a number, based on an algorithm. for instance if your next number is 5 digits long, a 6th digit would be added. That digit would be a number contrived using an algorithm over the other digits. this is probably more confusing than the help text, but this check digit ensures that the number has been created by the system and not entered by a person. So you might want to use this for voucher numbers or numbers that have to do with $$$. They are not used too much anymore.

Thanks Jean I got it.