# Bracket Symbols

Written by Jerry Ratzlaff on . Posted in Nomenclature & Symbols for Engineering, Mathematics, and Science

## Bracket Symbols

This is a list of the most common bracket symbols:

SymbolDefinitionExample
$$\left(\; \right)$$ parentheses, calculate expression inside first $$5\times \left(5+4\right) = 45$$
$$\left[\; \right]$$ brackets, calculate expression inside first $$\left[ \left(5+4\right) \times \left(9+4\right) \right] = 117$$
$$\{ \; \}$$ set, a collection $$a = {4, 5, 9 }$$
$$\lfloor a \rfloor$$ rounds number to lower integer $$\lfloor 5.4 \rfloor = 5$$
$$\lceil a \rceil$$ rounds number to upper integer $$\lceil 5.4 \rceil = 6$$
$$\left | a \right |$$ absolute value $$\left | -5 \right | = 5$$
$$\left \| x \right \|$$ normal