The Son of a Farming Family's Supporting Character Becomes Subo

"Our son is a born reader. He must study. He will surely achieve great success in the future!" I have been reincarnated as the short-lived son of a female supporting character in a novel. But I have absolutely no intention of dying in vain like that. 'Kang Gye,' the youngest son of a farming family, beloved by all. He has one secret that nobody knows. It's that he reincarnated with an 'Attendance System'! A genius brain that never forgets anything once seen, plus attendance check rewards! Although he was born as the sickly son of a farming family... With 'cheat keys' like these, there's no reason he can't achieve success, right? He challenges the civil service examinations to change...