Plus-minus Sign - Encodings

Encodings

• In ISO 8859-1, -7, -8, -9, -13, -15, and -16, the plus-minus symbol is given by the code 0xB1_hex Since the first 256 code points of Unicode are identical to the contents of ISO-8859-1 this symbol is also at Unicode code point U+00B1.
• The symbol also has a HTML entity representation of ±.
• On Windows systems, it may be entered by means of Alt codes, by holding the ALT key while typing the numbers 0177 on the numeric keypad.
• On Unix-like systems, it can be entered by typing the sequence compose + -.
• On Macintosh systems, it may be entered by pressing option shift = (on the non-numeric keypad).
• The rarer minus-plus sign (∓) is not generally found in legacy encodings and does not have a named HTML entity but is available in Unicode with codepoint U+2213 and so can be used in HTML using ∓ or ∓.
• In TeX 'plus-or-minus' and 'minus-or-plus' symbols are denoted \pm and \mp, respectively.
• These characters are also seen written as a (rather untidy) underlined or overlined + symbol. ( + or + ).