Question

Using the formula for squaring a binomial, evaluate the (999)².

Answer 1

Given (999)²

But we can write 999 as 1000-1

And also we know that (a – b)² = a²-2ab+b²

By applying the above identity we get

(999)² = (1000-1)²= 1000²-2(1000) (1) +1²

(1000-1)²=1000000-2000+1=998001