Equals sign
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The equal sign, equals sign, or =, used to indicate the result of some arithmetical operation, was invented in 1557 by Robert Recorde.
The = symbol that is now universally accepted for equality was first used by Robert Recorde in The Whetstone of Witte (1557). In the book (See image of page[1] (http://members.aol.com/jeff94100/witte.jpg)), he explains his design: to avoid the tediouse repetition of these woordes: is equalle to : I will sette as I doe often in woorke use, a pair of paralleles, or Gemowe [ie twin] lines of one lengthe, thus: =, bicause noe 2 thynges, can be maore equalle. According to the St Andrews University Maths History site[2] (http://www-history.mcs.st-and.ac.uk/Mathematicians/Recorde.html), " The symbol = was not immediately popular. The symbol || was used by some and æ (or œ), from the word 'æqualis' meaning equal, was widely used into the 1700s."
![[1]](http://members.aol.com/jeff94100/witte.jpg){kind=link}
The invention of the equals sign is commemorated in St Mary's Church, Tenby, Wales.
The symbol used to denote when something is approximately equal to something else is ≈, and the symbol used to denote when something is not equal to something else is ≠. The symbol ≡ is often used to indicate an identity rather than an equation.
See also
External links
- Earliest Uses of Symbols of Relation (http://members.aol.com/jeff570/relation.html)
- image of the page of The Whetstone of Witte on which the equal sign is introduced (http://members.aol.com/jeff94100/witte.jpg)