Question

Find the value of $199\times 201$.

• A. $39989$
• B. $40001$
• C. $39999$
• D. $400011$

Answer 1

The correct option is C $39999$

Given, $199\times 201$

$=(200-1)(200+1)$.

We know, $a^2-b^2=(a-b)(a+b)$.

Then,
$199\times 201$

$=(200-1)(200+1)$

$={200}^2-1^2$

$=40000-1$

$=39999$.

Therefore, option $C$ is correct.