mark or marks

[frindle2]

Hello. I understand "mark" is countable. But I'm confused which one is right in the context below.
Thank you.

----------------------
You should email your homerok to me in four days after the class. You'll lose 10 percent per day if your homework is late.
-> That means, "If you don't finish your homework on time, you'll lose part of your mark/marks."

 

[tedmc]

As you said, "mark" is countable.
You stand to lose marks if you submit your work late and you get lower marks.
You are confused (not confusing).

 

[allenman]

Not a teacher

..you'll lose part of your marks...

Understand that this is a regional expression. We do not say this where I am from. We would say ..you'll lose part of your grade
We said marks when I lived in Scotland, never in the US.

 

[MikeNewYork]

Yes, we use "grade/grades" in the US.

 

[Tdol]

In the UK, grade is often used for A-E results and mark for percentages.