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

Solution 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.

Solution 2:

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.