Question

Find the square of $71$ without multiplication.

Answer 1

Solution: ${71}^2=71\times 71=5041$
To make calculations easy, use the following approach:
$71=(70+1)$
So, ${71}^2$ $=$ ${70}^2+2\times 70\times 1+1^2$
$=4900+70+70+1$

$=5041$