# Symbol

## Symbol

A graphic sign established by convention to represent a magnitude, a number, an operation, a relationship, a mathematical or logical entity of a given nature.

• Symbols sometimes resemble the objects they symbolize, as does the symbol for the measure of an angle (∠), although this is rarely the case.
• Mathematical symbols are generally written forms that have been established through years or even centuries of use.

### Examples

Certain symbols are literal; they are letters that represent or correspond to a value, magnitude or operation; for example :

• letters in units of measure, such as m or cm;
• unknowns, such as the letter x in the equation x + 7 = 12 ;
• given numbers, such as a and b in the relationship a + b = b + a.

Certain symbols are numerical :

• Roman numerals, such as I, V, X, L, C, D, M;
• the ten Arabic numerals 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.

Certain symbols are grouping symbols :

• braces: { };
• brackets: [ ];
• parentheses: ( ).

Certain symbols are graphics that resemble the concepts they symbolize; for example :

• the symbol for the relationship of perpendicularity, ⊥;
• the symbol for the relationship of parallelism, //;
• the symbol that identifies an angle, ∠;
• the symbol for the relationship of approximate equality, ≈.