Sometimes it is advantageous to express a value in round numbers. To round to a particular place, look at the digit immediately to the right of the one you want to round to, in this case, the tens place. If that digit is 4, 3, 2, 1 or 0, zero it and everything to the right of it out. If that digit is 5, 6, 7, 8 or 9, increase your target digit by one and zero everything to the right of it out. If your target digit is 9, it will become a zero and increase the digit to the left of it by one.
It is 300 when rounded to the nearest hundred
916 rounded to the nearest hundred is 900
5800
0
It is already rounded to the nearest hundred thousandths. Rounded to the nearest thousands would be 87.381.
0
10000
0
0
678 is rounded nearest hundred is 700
10900
500