Plus and minus signs

The plus (+) and minus (−) signs are used universally to represent the operations of addition and subtraction, and have been extended to many other meanings, more or less analogous.

Though the signs now seem as familiar as the alphabet or the Hindu-Arabic numerals, they are not of great antiquity. The Egyptian hieroglyphic sign for addition, for example, resembled a pair of legs walking in the direction in which the text was written, with the reverse sign indicating subtraction. In Europe in the early 15th century the letters P and M were generally used.

The earliest appearance of the modern signs seems to come from a book by Johannes Widman in 1489. The + is a simplification of the Latin "et" (comparable to the ampersand &). The − may be derived from a tilde written over m when used to indicate subtraction; or it may come from a shorthand version of the letter m itself.

The plus sign can mean many different operations, depending on the mathematical system under consideration. Many algebraic structures have some operation which is called, or equivalent to, addition. Moreover, the symbolism has been extended to very different operations, such as concatenation of strings of characters.

Plus can mean:

• exclusive or (usually written ⊕): 1+1=0
• logical conjunction (usually written ∧): 1+1=1
• logical disjunction (usually written ∨): 1+1=1
• concatenation of string literals is sometimes written: "1"+"1"="11"

Table of contents

1 Plus and minus signs in other cultures 2 Unicode 3 External links 4 See also

Plus and minus signs in other cultures

A Jewish tradition dating at least from the 19th century is to write plus using a symbol like an inverted T. This practice was adopted into Israeli schools in the 1970s and is now commonplace in most elementary schools (including secular schools) and some secondary schools. It is also used occasionally in books by religious authors, but most books for adults use the international symbol "+". The usual explanation for the practice is that it avoids the writing of a symbol "+" that looks like a Christian cross. Unicode has this symbol at position U+FB29 "Hebrew letter alternative plus sign" (﬩).

Unicode

The minus sign is U+2212 (−); in HTML it can be represented as − or −.

The hyphen-minus sign is U+002D (-); it should be used for the minus sign only with fixed-width fonts.

External links

See also

• Equals sign
• Plus-minus sign
• Table of mathematical symbols