In the number 0.125, there is:
0 in the ones place,
1 in the tenths place,
2 in the hundredths place, and
5 in the thousandths place.
We want to round to the hundredths place, which is 2.
To do this we must look to the next digit.
If it's less than 5, we round down.
If it's more than 5, we round up.
The next digit is 5, though! So what do we do then?
Well, we would look to the next digit again and decide from that.
There isn't really a next digit to decide from, though, is there?
In that case, we just round up.
and we get 0.13