Operations with signed numbers

Adding a positive number moves right on the number line; adding a negative moves left. Subtracting a number is adding its opposite: \(a-b=a+(-b)\).

For multiplication and division, equal signs give a positive result and different signs give a negative result. Division by zero is undefined.

Example

\(\begin{aligned}-5-(-8)&=-5+8\\&=3\end{aligned}\)

\((-6)(-4)=24\), while \(24\div(-6)=-4\). A negative times a negative is positive so that multiplication remains consistent with distribution: \((-6)(4+(-4))=0\).

Brackets determine the base of a power: \((-3)^2=9\), but \(-3^2=-(3^2)=-9\).