57, as 0.4 is closer to zero than one, you must round down.
570
574 km2
14.49 rounded to the ones place is 14.
90.763 rounded to the ones place is 91
It is already rounded to the nearest ones.
831 is already rounded to the ones place.
56.4059 rounded to the ones place is 56
600
23.09 rounded to the nearest ones = 23
54.38 rounded to the ones place is 54.
10.49 rounded to the nearest ones is 10.
441.031 rounded to the nearest ones = 441