Digit or number?

Question

A reader recently asked, "What's the difference between a digit and a number?"

Answer

Good question! The words digit and number can be confusing because they are closely related and often used in the same contexts, as in these examples:

• David asked for her phone number and she took out a piece of paper and wrote something. But when she gave it to David, something was missing; there were only six digits.
• Please email me your 10-digit confirmation number.

However, digit and number have very distinct meanings.

Digit

A digit is any one of these symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. For example, the number 23 is written with two digits, 2 and 3.

Number

A number is an amount of something. It can be written with one or more – or many – digits. Numbers can also be written with words. A number can also be a series of digits that is used to identify something, such as a phone number, apartment number, or social security number.

These are all examples of numbers:

• 2
• 49
• forty-nine
• 12,446
• nineteen hundred and fifty-six
• 212-555-6051

I hope this helps.