A binary operator representing plus-or-minus that indicates two possible values in equations and intervals.
Examples
Plus or minus in a quadratic formula solution
x = -b \pm \sqrt{b^2 - 4ac} \over 2a
Error margin notation
\text{Length} = 5.37 \pm 0.02 \text{ cm}
Double equation with opposite signs
x \pm y = z \implies x = z \mp y