Evaluate:

0.000645 × 82.3

Let x = 0.000645 × 82.3

Taking log on both side we get,

⇒ logx = log (0.000645 × 82.3)

= log 0.000645 +log 82.3 (since, log a × b = log a +log b)

= ̅3.1904 + 1.9153

= –3.1904+1.9153

=–1. 2751

⇒ logx = –1.2751 = ̅1 . 2751

⇒ x = antilog ̅1.2751 = 0.05307