Many scraps of paper later a four-digit number emerged, but it was the wrong one.
It draws a four-digit number in the style of Pick 3.
The scarcity of four-digit numbers means that there is a waiting list for them.
It sounded extraordinary, since there are 10,000 possible four-digit numbers.
She picked up a phone and tapped in a four-digit number.
Finally a four-digit number is used to uniquely identify the vehicle.
Take any four-digit number, using at least two different digits.
In this new naming system, components were given four-digit numbers starting with 2.
The number 6174 has the same property for the four-digit numbers.
Leading zeros were added as necessary to give a four-digit number.