5984 - 9 is on the hundred's place
5984 - 8 is on the right side of the hundred's place
For you to determine whether or not the number is to be rounded up or down, all you have to do is take note of the number on the right side of the hundred's place
If the number is 5-9 then you have to round it up BUT if the number is 0-4 then you have to round it down. Since in this case, 8 is under 5-9 range then we will round it up.
In this case you'll have:
5984 rounded up to the nearest hundred's as 6000