Lesson 4.3: Ratios and Percents
Ratios are often indicated by the use of the fraction line or the ratio sign. A ratio relates two quantities through the operation of division; it is read, "is to." The braille symbol for ratio is dot five dot two. Thus, the braille symbol for a ratio is a two-cell symbol. In print, the symbol that is used has the same appearance as a print colon, that is, two dots, one above the other. In braille, however, the literary colon should not be used, as its configuration is the same as the Nemeth numeral three. The sign for ratios is a mathematical sign of comparison and is not a colon. It should not be used as a mark of punctuation, nor should a mark of punctuation be used for ratio. The print representation of this symbol may show no spaces between it and the numerals or expressions associated with it. In braille, however, a space must be placed before and after the symbol because it is a sign of comparison.
The symbol used to show percent in braille is a two-cell symbol, dot four, dots three five six. As with monetary signs, a dot four is placed in the first cell. The second cell is composed of the dots three five six, the same configuration as the numeral zero. Since the second cell could be construed as the numeral zero, it is important to be vigilant in both the brailling and reading of this symbol to prevent confusion.
As with the cent sign that appears most often to the right of a numeral or other character, the percent symbol is unspaced from the numerals or characters to which it refers or is applied. It occupies the same position in braille as it does in print. That is, if it follows a numeral or other character in print, then it follows the numeral or character in braille. The percent symbol is a mathematical symbol that must be brailled according to any other rules which apply to mathematical symbols.