Answer:
20.086
Explanation:
The result is 20.0855.... The digit in the 4th decimal place is 5, so the digit 5 in the third decimal place gets increased to 6 by the rounding.
Any scientific or graphing calculator can do this for you, as can many online calculators, and any spreadsheet. The spreadsheet formula is =ROUND(EXP(3),3).
e³ ≈ 20.086