Five hundred at a rough estimation - with banners and sticks - mostly just yelling abuse.

With numbers so large, the inexactitude of rough estimation is needed.

Also, the example uses relatively specified numbers, while in reality there are often just rough estimations.

By his own frank admission and rough estimation, he has spent as much as $10,000 a month on dress suits.

These are all fairly rough estimations, and I weighed things on a bathroom scale, but you get the general idea.

"Dead probably between thirty and forty hours, by my rough estimation."

So, is there any rough estimation like not before X or not after Y?

There are about 10 fundamental particles in the observable universe, by rough estimation.

I assume we could use those to do a rough estimation on when legacy digital will be shut down.

The maximum size is subject to debate because some reports are rough estimations or speculations performed under questionable circumstances.