Do you know what the report card is based upon?
That might help in terms of understanding why the marks seem so different from what you'd have (otherwise quite reasonably) expected to be the case.
I doubt that the teacher will be surprised that you've asked to discuss it.
My advice to you might be a little unwelcome at this point-- but here it goes:
keep an open mind and ask for help UNDERSTANDING the report card-- what is is based upon? What kinds of data make up the marks you're seeing? Why are those things being marked so low?
Now, you may well walk away from that meeting feeling grumpy and as though the teacher is targeting your child, or as though s/he is pressuring for an ADD/ADHD diagnosis or something...
or that the grading scheme, while fair/consistent, isn't "academic" in nature, but is primarily behavioral instead.
But at least you'll know.
