The extra digits were something of a thank you.

Verizon said that the four extra digits would be needed even on calls within the same area code.

If you're making a payment for a previous tax year you need to add extra digits to the reference.

The basic idea is to have one or more extra digits in the code.

At the time of the change, an extra digit was added to the subscriber number.

The extra two digits describe a position within the 1-kilometre square.

To finish off we may need to emit a few extra digits.

Brittany ran ahead to try to see if they did, indeed, have extra digits.

From about the start of the 1960's an extra digit was needed for new devices.

The number 100 has two extra digits; its logarithm is 2.