Well, first start off by adding commas where they are needed (after every third place). I find that this helps A LOT when dealing with bigger numbers.
So, 555,000 is your number. You have to look in the ten thousands place. You have a 5 in the ten thousands place. From here, you look at the number directly to the right of the number you need to round. The number next to the 5 in the ten thousands place is a 5. When rounding, numbers that are 5 or over have to be rounded out. So, this would be the rounded answer you are looking for.
560,000
I hope this helps :)