Mona Gray is a 20-year-old loner who, as a child, turned to math for salvation after her father became ill. As an adult, Mona now teaches the subject and must help her students through their own crises.
An Invisible Sign, An 1nvisible Si6n, An Invisible Sign of My Own, I numeri dell'amore, Láthatatlan jel, Matemática do Amor, Matematika ljubavi, Neredzamā zīme, Niewidzialny znak, Señal invisible, Slaptas ženklas, To aorato simadi, Um Sinal Invisível, Un semn invizibil, Una señal invisible, Невидим знак, Невидљиви знак, Таємний знак, Тайный знак, ジェシカ・アルバの“しあわせの方程式”