# How do you evaluate (1.4\times 10^ { 5} ) - ( 6.2\times 10^ { 4} )?

Feb 20, 2017

You first convert, so that the $10$-powers are equal.
$1.4 \times {10}^{5} = 1.4 \times 10 \times {10}^{4} = 14 \times {10}^{4}$
$= \left(14 \times {10}^{4}\right) - \left(6.2 \times {10}^{4}\right) = \left(14 - 6.2\right) \times {10}^{4} = 7.8 \times {10}^{4}$
If significance is important this should be rounded to $8 \times {10}^{4}$