Round to the nearest hundred thousand. 636,665

600,000

Step-by-step explanation:

I think that it will be 600,000 because the 3 is below 5 which you can not round anything that is below 5.This what I look at when i Round and it may or may not be helpful to other people:

5 or more raise the score

4 or less let it rest

That is what I learned.