Answer
$.0000166$
Work Step by Step
We are given the number $1.66\times10^{-5}$. Since the exponent is negative, move the decimal 5 places to the left.
Note that 5 places to the left will be 4 decimal places past the first digit (1), so we will add 4 zeroes before 1.
$1.66\times10^{-5}=.0000166$