Question

Using identities, evaluate
$1.5\times 9.5$

Answer 1

Given $10.5\times 9.5$
$=(10+0.5)(10-0.5)$
Using $(a^2-b^2)=(a+b)(a-b)$ identity,
$=(10{)}^2-(0.5{)}^2$
$=100-0.25$
$=99.75$

Hence, $1.5\times 9.5=99.75$