Get The Math Straight

The following headlines are currently running -- I'm not sure how to link to them:

On Yahoo's main screen "Tens of Thousands Rally For Abortion Rights"

Click on that story headline and the headline becomes "Thousands March For Abortion Rights"

Then read deeper into that same story in the body copy and it says, "Authorities no longer give formal crowd estimates, but various police sources informally estimated the throng at between 500,000 and 800,000 strong."

So when is 800,000 = to "tens of thousands" exactly? Seems a little misleading.