Round to nearest ten thousandth:
4.803621
http://www.enchantedlearning.com/math/decimals/placevalue/gifs/ex.GIF
To round the number 4.803621 to the nearest ten-thousandth, you need to look at the digit at the fifth decimal place, which is the ten-thousandth place.
The digit in the ten-thousandth place is 2.
Since 2 is less than 5, you don't need to make any changes to the original number.
Therefore, rounding 4.803621 to the nearest ten-thousandth would simply be 4.8036.