This site is supported by donations to The OEIS Foundation.

# Negative numbers

(Redirected from Negative number)
Jump to: navigation, search

This article page is a stub, please help by expanding it.

Negative numbers are real numbers that are less than 0. Negative numbers are written with a minus sign "−" preceding the absolute value, e.g., −47. This can be thought of as a shorthand for 0 − 47.

Multiplying a negative number by −1 gives its absolute value, e.g., ${\displaystyle |-{\frac {5}{8}}|=(-1)(-{\frac {5}{8}})={\frac {5}{8}}}$.

The square of a negative number ${\displaystyle x}$ is a positive number, and in fact ${\displaystyle x^{2}=(-x)^{2}}$; but the square root of that negative number is a purely imaginary number of the form ${\displaystyle i{\sqrt {|x|}}}$, where ${\displaystyle i}$ is the imaginary unit. For example, ${\displaystyle (-49)^{2}=2401}$, but ${\displaystyle {\sqrt {-49}}=7i}$.