124 rounded to the nearest hundred would be 100. When rounding a number to the nearest hundred, you look at the digit in the tens place. If it is 5 or greater, you round up; if it is less than 5, you round down. In this case, the digit in the tens place is 2, which is less than 5, so you round down to the nearest hundred, which is 100.
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