1397 x 1397 = ?

Answer: Option A

$$\begin{array}{rl}& 1397\times 1397\\ & ={\left(1397\right)}^2\\ & ={\left(1400-3\right)}^2\\ & ={\left(1400\right)}^2+{\left(3\right)}^2-\left(2\times 1400\times 3\right)\\ & =1960000+9-8400\\ & =1960009-8400\\ & =1951609\end{array}$$