How old are they?
When I was a kid, our 1-6 grades were letters (E, G, S, N) that generally corresponded to "above, at, below, well below expectations" The point was to detect what needed extra attention and to help guide focus of the parents and teachers. 30 years later my kids have the same thing but the labels are a bit different. Grades 7-8 introduce A-F and then high school is just percentages.
I've also seen the opposite in a relative's reaction to their kid getting number grades. They fixated far too much 3 or 4 points either way and not the general signal.
When I was a kid, a grade below 75% average on all your subjects will make you repeat the level. I think that is not allowed now (repeating a level). My kids are now 5 & 9. They are on an IB program school. They show us a chart of where your kids lands statistically compared to other kids. I don't know where the statistics is derived from. I don't get a straight answer if every time I ask where the progress graph is taken from.
Oh the fixation for the 3 to 4 points is a thing in the school when I was young, but not in our family. My classmates families will fight for a point to get the highest honor. One family even exited the school before graduation because he didn't get the highest average and finished his schooling in the rival school.