#### Answer

$8\times10^{-3}$

#### Work Step by Step

We start with the given expression: $4(2\times10^{-3})$
We rewrite the expression using the associative property: $4\times2\times10^{-3}$
We multiply the first two terms: $8\times10^{-3}$
The number is now in scientific notation, as 8 is between 1 and 10, and -3 is an integer.