It is 12.2
Most schools wrongly teach you to always round a half up (so the answer would be 12.3) but, while this is a simple rule to teach, it is not really correct. Under this rule:
1860
It is: 12.4
The number is already rounded to exactly that degree.
The answer is 18.2
10
755.3
It is 1.01 when rounded to the nearest hundredth
7.3
0.1
410000
100
The answer is 210,000,000