(i) 51² - 49² =

Using Identity

Here a = 51, b = 49

(ii) (1.02)² - (0.98) ²

Using Identity

Here a = 1.02, b = 0.98

(iii) (153)² - (147)²

Using Identity

Here a = 153, b = 147

(iv) (12.1) ² - (7.9) ²

Using Identity

Here a = 12.1, b = 7.9