linguistic:voice_change, structural:reformatting
Minus sign

The minus sign (−) has three main uses in mathematics:

In many contexts, it does not matter whether the second or the third of these usages is intended: −5 is the same number. When it is important to distinguish them, a raised minus sign (¯) is sometimes used for negative constants, as in elementary education, the programming language APL, and some early graphing calculators.

All three uses can be referred to as "minus" in everyday speech, though the binary operator is sometimes read as "take away". In American English nowadays, −5 (for example) is generally referred to as "negative five" though speakers born before 1950 often refer to it as "minus five". (Temperatures tend to follow the older usage; −5° is generally called "minus five degrees".) Further, a few textbooks in the United States encourage − x to be read as "the opposite of x " or "the additive inverse of x "—to avoid giving the impression that − x is necessarily negative (since x itself may already be negative).

In mathematics and most programming languages, the rules for the order of operations mean that −5 is equal to −25: Exponentiation binds more strongly than the unary minus, which binds more strongly than multiplication or division. However, in some programming languages (Microsoft Excel in particular), unary operators bind strongest, so in those cases −5^2 is 25, but 0−5^2 is −25.

Similar to the plus sign, the minus sign is also used in chemistry and physics. For more, see § Other uses below.