What do you call each individual component of a number: a “digit”, a “figure”, or “place”?

Question

What are the individual 0, 1, 2, "letters" etc. in numbers called? I know the word "digits", I've seen "n-figure salary", and Google translation (from German "Stellen"), when used in a sentence, yields "places" ("How many places does this number have?"). And exactly when is the English cognate of our German word "Ziffer", "cypher", used? Because "Ziffer" really means "digit" in English, I think …

Answer 1

"Digit" refers to the characters used to write out a number. "Places" refers to the number and location of digits needed to write out the number. "n-figure" is simply a count of the digits needed ignoring any fractional part.

1,234 - Uses digits 1, 2, 3 and 4; has four places; is a 4-figure number

100,111 - Uses digits 0 and 1; has 6 places; is a 6-figure number

905.001 - Uses digits 0, 1, 5 and 9; has 6 places; is a 3-figure number

As a reminder: , is used to split thousands, millions and so on. . is used to split of the decimal places. The term "places" is often used to specify only the decimal places:

This is accurate to 3 decimal places.

This phrasing can be reworded as:

This is accurate to the 1/1,000th place.

Answer 2

"Digits" is the correct term. "Figures" is occasionally used when referring to money, but that's informal.

"Numeral" is correct when referring to the representation of the digits themselves. "One" is an intangible concept, which is represented by a particular numeral, a vertical stroke.

Answer 3

The correct word for German "Ziffer" is digit.

Sometimes one also says Arabic Numerals to differentiate from Roman Numerals.

Both systems can represent the same numbers (e.g. XV and 15).

Answer 4

If you are talking about the individual "letters", it would have to be a digit, which has the no positional or directional reference. Both "n-figure salary" and "places" do not refer to the individual representation of the letter, but are related to the total number of digits.