I'm assuming the range is 1 - 10, based on real life.
I do know how the grades for children and teens correspond:
C = 6, B = 8, A = 10.
So that's a guide. I don't know if it is the same here, because an A+ would be higher than 10 which seems unlikely.
There is some time to figure this out, I probably won't have finished my scoring game until the final day.