Let's arrange the following decimals and add them together, rounding the answer to the nearest ten-thousandth:

The numbers are:

$5.93,\ 11.862,\ 284.0382,\ 88.44$

Step 1: Addition

$5.93 + 11.862 + 284.0382 + 88.44 = 390.2702$

Step 2: Rounding to the nearest ten-thousandth

The result $390.2702$ is already at four decimal places, so rounding to the nearest ten-thousandth:

$\boxed{390.2702}$

This is the final answer rounded to the nearest ten-thousandth.

Would you like details or have any questions about this?

Here are 5 related questions you might find interesting:

1. How do you round a number to the nearest thousandth?
2. What is the difference between truncating and rounding?
3. How can you add numbers more efficiently using mental math techniques?
4. How do you deal with decimals when adding large sets of numbers?
5. How do decimal places affect the accuracy of calculations?

Tip: When rounding to a specific decimal place, always check the digit immediately after the required place to decide if you round up or leave it unchanged.