Which form is correct to find ( 999^2 )?

Correct answer: ( (1000-1)^2 )

The correct answer is option B: \((1000-1)^2\). The number 999 is one less than the convenient base 1000, so write \(999=1000-1\). Therefore \(999^2=(1000-1)^2\). Using \((a-b)^2=a^2-2ab+b^2\), we get \(999^2=1000000-2000+1=998001\). Option A, \((900+99)^2\), is numerically equal to 999 squared, but it is not the intended convenient identity form and is less efficient. Option B is the best and correct form because it uses a nearby round number. Option C represents \(1001^2\), not \(999^2\). Option D represents \(108^2
eq999^2\). Memory cue: numbers just below a power of 10 are written as base minus 1.