Chapter 4: Revolt of the Arithmetic Sequence

Nam Haeng Seon is trying to get her daughter enter a special 7-student class, for which her daughter qualifies, but one of the mom's makes things complicated which get Haeng-Seon's daughter replaced with another student. Chi-Yeol goes to the principal in protest, but is pushed against the corner and his protest fails. In secret, he offers to teach Chi-Yeol's daughter in his spare time in return for Chi-Yeol's free meals.