Lesson 1.3: Comma
The mathematical comma, dot six, has many uses in mathematics. Even when the comma is used as a mark of punctuation, with numbers, variables, terms, and mathematical expressions, the mathematical comma is to be used. The literary comma, dot two, is to be used following a word or other literary expression.
Because the literary comma (dot 2) would be confused with the numeral, 1, which is also formed by brailling dot 2, the mathematical or Nemeth comma must be used instead. This use of the comma simplifies the written form of numbers such as 11,111.
The mathematical comma is also the symbol to be used as a mark of punctuation when a comma follows a mathematical symbol. When it is used in this manner, the mathematical comma, dot six, should be used rather than the literary comma, dot two. A space must follow the comma. If a number follows a comma, the number must be preceded by the numeric indicator since the number follows a space. The only exception is when a number is in an enclosed list; refer to Chapter ten.
The literary comma must be used as a mark of punctuation if it follows material that is composed of a word or literary expression, such as an abbreviation. This rule applies even if the words are associated with Nemeth numerals. The numerals, however, are always to be in Nemeth notation. Refer to Chapter seven for more information on abbreviations.
Use of the literary comma:
Use of the mathematical comma:
The comma as a place value separator
The comma is used in mathematics to divide long numbers into smaller units, aiding in the identification of place value. In a number that is separated into short segments, the comma is a numeric symbol rather than a mark of punctuation. Consequently, there should be no space before or after the mathematical comma. Numerals that are longer than one line of braille must be divided after a comma.