Answer: 3.8 * 10^-3 (10 to the negative third power)
Explanation:
First, you would find the leading digit which is 3. Then, include the following digits after the decimal. The following digit is 8 so you have 3.8. After that, you count how many places the decimal point would move until it's after three. (3 places) And since the number is smaller than 1, the exponent is negative.