Evaluate: 9.8 × 10.2

Solution:

Given, 9.8 × 10.2 = (10 + 0.2)(10 - 0.2)

Using standard identity: a² - b² = (a + b)(a - b)

Here, a = 10 and b = 0.2

9.8 × 10.2 = (10 - 0.2) (10 + 0.2)

= 10² - (0.2)²

= 100 - 0.04 = 99.96

✦ Try This: Evaluate: 9.6 × 10.4

Given, 9.6 × 10.4 = (10 - 0.4) (10 + 0.4)

Using standard identity: a² - b² = (a + b)(a - b)

9.6 × 10.4 = (10 - 0.4) (10 + 0.4)

= 10² - (0.4)²

= 100 - 0.16 = 99.84

☛ Also Check: NCERT Solutions for Class 8 Maths Chapter 9

NCERT Exemplar Class 8 Maths Chapter 7 Problem 86(xiv)

Evaluate: 9.8 × 10.2

Summary:

Evaluating 9.8 × 10.2 we get, 99.96

☛ Related Questions:

• Evaluate: 10.1 × 10.2
• Evaluate: (35.4)² - (14.6)²
• Evaluate: (69.3)² - (30.7)²