Question

How can you express $997$ so that the expression ${997}^2$ can be calculated using an algebraic identity?

• A. 990+7
• B. 995+2
• C. 1000-3
• D. 1005-8

Answer 1

The correct option is C 1000-3

To find the square of large numbers,the numbers are expressed as a sum or difference between 100,1000 etc and another single digit.
For example to find the square of 97, it can be expressed as $(100-3{)}^2$

To find the square of 103, it is expressed as $(100+3{)}^2$

Hence 997 can expressed as
$997=1000-3$.