Question

What is the value of ${248}^2-{249}^2$?

Answer 1

Find the value of ${248}^2-{249}^2$.

$\begin{array}{rcl}{248}^2-{249}^2& =& \left(248+249\right)\left(248-249\right)\left\{\mathrm{Use}{a}^2-b^2=\left(a+b\right)\left(a-b\right)\right\}\\ & \Rightarrow & {248}^2-{249}^2=497\left(-1\right)\\ & \Rightarrow & {248}^2-{249}^2=-497\end{array}$

Hence, the required value of$\begin{array}{l}{248}^2-{249}^2\end{array}$is $-497$.