Hi, Allan

I would like to ask you about quiz #5 in Module 7.
The question was:
Correcting every written mistake that students make is a good way to help encourage students.

Especially, I was a little bit confused about the point of 'correcting EVERY written mistake'.
Does it mean that crossing a lot of checks in the text which makes the text messy instead of writing some important words on the margin or underlining below the wrong sentence?

Thank you