Number Lines for Rounding Numbers

Here's a snippet from our lesson on rounding today:

One of the largest animals ever found was a blue whale that weighed 183 tons.  Is 183 tons closer to 100 tons or 200 tons?

Which two tens is 183 between?  Which ten is it closer to?

After students talked in their table groups to figure this out, they attempted to convince the rest of the class their answer was right.

Here are the results of one class' discussion:

Most groups mentioned comparing 183 to a half-way number (150 when rounding to the nearest hundred and 185 when rounding to the nearest ten), then compared the distances to the nearest multiple.

I was very impressed with one group, who shared that when rounding 183 to the nearest hundred, first, they found the closest landmark/benchmark number (180).  Then they thought about the distance to the nearest multiple of 100 in tens.  Do you think this strategy would work for any number you're trying to round?  Why or why not?  If you can think of an example of when it wouldn't work, tell us about it in your comment.