safe?

i'm sure school is creating future safe crackers!
i've been here now for too long, many say (esp. the headmaster!), and i've yet to work out how to open one of these lockers.
apparently you twist the dial clockwise to the first number of your code. then anticlockwise PAST your next number before returning to it and .... i give up!
the kids don't use them anyway as it's macho to walk around with the world on your back! (drives me into HUGE lectures on bone development etc!)