Question

Evaluate the following (using identities):

$104\times 95$

Answer 1

$104\times 95$
$=(100+4)(100-5)$
$={100}^2+(4-5)\left(100\right)+4(-5)$ [Using $(x+a)(x+b)=x^2+(a+b)x+ab$]
$=10000-100-20$
$=9880$