Question

evaluate the following :- a)1999 × 2001​

Answer 1

Step-by-step explanation:

Rewrite as :

(2000-1)(2000-1)

(2000-1)^2

apply the identity (a-b)^2

(2000)^2 -2×2000×1+(1)^2

4000000-4000+1

3996001