Why does Meg have academic difficulty in school even though she is very bright? Why does she have social difficulty?

Meg is portrayed as an awkward girl who doesn't do particularly well in school nor fit in with the popular crowd. However, this apparent mediocrity conceals her extraordinary math abilities - a subject her father taught her before he disappeared.

Meg's chief struggle in the book involves the challenge to either disown or embrace her particular genius and idiosyncrasies. Ultimately she learns that her personal differences are weapons in her own fight against the Dark Thing, and her efforts to save her father.