WBCS.LIVE practice question

What is the value of (999² - 998²)?

Solve this multiple-choice question and check the correct answer with its explanation below.

Answer options

  1. 1
  2. 1997
  3. 1999
  4. 2001

Correct answer and explanation

Correct answer: 1997

Explanation: ✅ Correct Answer: (B) 1997 📚 Explanation: Step-1: Use the algebraic identity a² - b² = (a + b)(a - b). Here, a = 999 and b = 998. Step-2: Calculate (999 + 998) x (999 - 998). Step-3: (1997) x (1) = 1997. This is a much faster method than squaring each large number individually.