If a child got 52% in a mock, what grade is that?

[ImFuminHun]

If they got 33 out of 63 (52%) what grade is that?

I've been Googling but it appears to be a different answer for different subjects.

This is geography.
Could anyone help?

To interpret grades, you need:

Exam type (A level, GCSE etc)
Board
Paper type - Foundation, Higher
Subject

That should give a ball park grade.

Depends. Higher or foundation and on the year of the paper