Write \( \frac{2}{5} \) as a decimal. \( \frac{2}{5}=\square \) (Round to four decimal places as needed.)

To convert \( \frac{2}{5} \) into a decimal, you can simply perform the division: 2 divided by 5 equals 0.4. Since this result only has one decimal place, it can be expressed as 0.4000 when rounded to four decimal places. Thus, \( \frac{2}{5} = 0.4000 \).