To round to nearest hundred, look at the tens digit: if it is 5 or more round up otherwise round down; 2 is not 5 or more, so round down:
5921 → 5900 to the nearest hundred.
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.
0
10000
0
678 is rounded nearest hundred is 700
0
10900
500
3300