Mona Gray is a second grade math teacher for whom math is not only a
job, but a beloved friend, an obsession and a security blanket. In this first novel we
learn about the events that have shaped her (such as the "illness" of her mathematician father) and her "creative" teaching
methods.
Math certainly is a major theme of this book. However, its idea of math is a bit strange (mostly what she seems to do with the students in her math class is find objects in nature that look like numbers...which isn't exactly math), and moreover it seems to present the idea that math is an obsession of people who are too broken or scared to really live. For instance, the title refers to a neighbor who always wore a wax number around his neck indicating his level of happiness, until he realized that he could be a happy person instead of a number; Mona "wears and invisible sign of her own". [Needless to say, this is not at all how I think about math. I see it as something beautiful and important and perfectly compatible with an ordinary, happy life.]
Contributed by
Anonymous
Quirky and fun. Unique and intriguing writing style. Loved it.

Thanks to Vijay Fafat for pointing out to me that a film adaptation of this book, called simply "An Invisible Sign" starring Jessica Alba was released in 2010. The film is very much like the book, adding some cool graphics in the form of a fantasy story her father tells her and "floating numbers" when she obsessively knocks on wood.
