I'm a Professor, But She Called Me 'Little Brother'

Lu You, a world-renowned math professor, prided himself on his perfectly peaceful, albeit solitary, routine. But a sudden, bizarre accident shatters it all, flinging him into the body of a 15-year-old boy in a surprisingly familiar yet subtly different world. Gone is his esteemed position, replaced by a handsome face, an affluent family, and... abysmal grades.