*shrugs* maybe he dropped a course second semester, and had to pick up an extra, so having already done that years math first sem, he picked up the next year's as well in second sem?
And holy. 17 could put them either late schoolyear birthdays, (so grade 11) or in grade 12...
Theyre same grade, right? How would Rune have notes on the math that Luck is learning this semester (first sem of the schoolyear)??? He doesnt have math class