# How do you write the answer in scientific notation given (2.1times10^-4)/(8.4times10^-6)?

Apr 16, 2017

$2.5 \times {10}^{1}$

#### Explanation:

$\frac{2.1 \times {10}^{- 4}}{8.4 \times {10}^{- 6}}$

$= \frac{0.00021}{0.0000084}$

$= \frac{2100}{84}$

$= 25$

$= 2.5 \times {10}^{1}$

Apr 16, 2017

$2.5 \times {10}^{1}$

#### Explanation:

Use the exponent rule ${x}^{m} / {x}^{n} = {x}^{m - n}$

$\frac{2.1 \times {10}^{-} 4}{8.4 \times {10}^{-} 6} = \frac{2.1}{8.4} \times {10}^{- 4 - - 6} = 0.25 \times {10}^{2}$

Scientific notation requires a non-zero number to be to the left of the decimal point. This means you need to move the decimal to the right one place which decreases the exponent by 1:

$0.25 \times {10}^{2} = 2.5 \times {10}^{1}$