Equals sign

The equals sign or equality sign (=) is a mathematical symbol used to denote equality. Invented by Robert Recorde in 1557. In an equation, an equal sign is placed between two expressions that have the same value. In Unicode and ASCII, this is U+003D = equals sign.

History

Until the 16th century, all mathematicians used their own equal signs, and the lack of a common notation made it difficult for them to understand each other. Robert Recorde first used it in his 1557 work The Whetstone of Witte, saying: "Rather than using the word equals tediously over and over again, I will put two parallel lines, as I usually do when working, because nothing can be more equal than two parallel lines."

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