Question

Compute the value of following expression $201\times 199$

• A. $39989$
• B. $39899$
• C. $39999$
• D. $39998$

Answer 1

The correct option is C

$39999$

The given expression is

$201\times 199$

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

$=(200{)}^2-(1{)}^2\left[\right(x-y\left)\right(x+y)=x^2-y^2]$

$=40000-1$

$=39999$