Lesson 5.5 Directed or Signed Numerals
There are indicators in UEB that apply to the item appearing just before or after the indicator. An item is defined as any one of the following groupings if they appear in the position affected by the indicator:
- An entire number, i.e. the initiating numeric symbol and all succeeding symbols within the numeric mode thus established (which would include any interior decimal points, commas, separator spaces, or simple numeric fraction lines).
- An entire general fraction, enclosed in fraction indicators.
- An entire radical expression, enclosed in radical indicators.
- An arrow.
- An arbitrary shape.
- Any expression enclosed in matching pairs of round parentheses, square brackets or curly braces.
- Any expression enclosed in the braille grouping indicators.
- If none of the foregoing apply, the item is simply the next individual symbol.
The symbols for plus and minus are also used to indicate directed or signed values. In most cases there is no distinction between a plus or minus sign used as a sign of operation or used to indicate a directed numeral or symbol. A directed numeral designates a value as positive by using the plus sign, or negative by using the minus sign before the numeral or symbol. Usually if a number is positive, the plus sign will not be shown. However, in some cases the plus sign is shown. The plus and minus signs may also be in the superscript position. The level change up indicator places the next item in the superscript position. Grade 1 indicators must be used with the level change up indicator unless grade 1 mode has already been established.
A grade 1 symbol indicator is used with the first level change up indicator in Example 8. The numeric indicator turns on grade 1 mode for the second level change up indicator in the expression. Grade 1 mode set by the numeric indicator is only terminated by a space, hyphen, or dash.