I understood it as Eunho was really clever as a child and so him saying "i don't really want to spend it in school" and Jaeha sarcastically agreeing is because Eunho probably excels in school and doesn't need to really be there? since he was able to do high school maths even when Jaeha himself, was clueless. I might be wrong tho!! (๑•ㅂ•)و✧
It means eunho is a smart kid ...but and also i m re reading this whole story once again..
thanks guys, ur right. the chapters after this one also imply that eunho is a smartie
The official translation on Lezhin on this scene is as following,
Eunho: "Being here for a few hours doesn't hurt my studies that much"
(My friends from the school club probably hate me, but...)
Jaeha: Okay, genius
.
and the flashback is as shown.
Actually, the fan translated version has mistakes here and there compares to the official translation. I just found out after rereading the official version of the series too.
so I'm re-reading Lover Boy for the fun of it, you know how it's always better reading it the second time, but I'm not sure what the author is trying to portray in this page when Jaeha thinks about the time when he was doing homework w/ Eunho but it's highschool math?
http://www.mangago.zone/read-manga/lover_boy_lezhin/uu/lover_boy_lezhin-chapter-5/29/