Answer: 503,000
Explanation:
The best way to understand the concept is to look at a round to the nearest thousand example: what is 52437 rounded to the nearest thousand?
As the hundredth digit is 4, which is less than 5, the number should be rounded down to 52000. As for 52678, as the hundredth digit is 6, which is larger than 4, it will be rounded up to 53000.