It’s on a 6 point scale and it’s also based on percentage, so all A’s are not equal. Highest grade achievable is 6.0. AP classes on 6 point scale, pre-ap classes on a 5 point scale and core classes are weighted on a 4 point scale. So you could have 5.5 grade in ap biology and the best grade you can earn in pre-ap is a 5. Most valedictorians end up with a gpa hovering north of 5.0.