Well, isn't that a happy little question! If we want to round 5600 to the nearest hundred, we look at the digit in the tens place, which is 6. Since 6 is greater than or equal to 5, we round the hundreds place up to 6000. Just like that, we've created a lovely rounded number that's easy on the eyes.
5600
5600
5600
It is 300 when rounded to the nearest hundred
0
5600
5600
5600
5600
5600
5600
5500
5,600
It is 300 when rounded to the nearest hundred
916 rounded to the nearest hundred is 900
0
It is already rounded to the nearest hundred thousandths. Rounded to the nearest thousands would be 87.381.