# How do you multiply (2times10^-4)times(4times10^-3) and write the answer in scientific notation?

Dec 13, 2016

$8 \times {10}^{-} 7$

#### Explanation:

To solve this problem first redistribute the terms to group like terms:

$2 \times {10}^{-} 4 \times 4 \times {10}^{-} 3$

$2 \times 4 \times {10}^{-} 4 \times {10}^{-} 3$

$\left(2 \times 4\right) \times \left({10}^{-} 4 \times {10}^{-} 3\right)$

$8 \times \left({10}^{-} 4 \times {10}^{-} 3\right)$

Now we can use the exponent rule for multiplying common terms with exponents:

$\textcolor{red}{{x}^{a} \times {x}^{b} = {x}^{a + b}}$

$8 \times {10}^{- 4 - 3}$

$8 \times {10}^{-} 7$