One Plus One Equals Blue

Twelve year-old Basil knows he's special—he's been associating numbers with colors since he was a kid. His gift (or curse) has turned him into somewhat of a loner, but his world begins to change when he meets Tenzie, the new girl in school who has similar freakisms. She, too, has synesthesia (a condition in which one type of stimulation evokes the sensation of another). At first, Basil is somewhat annoyed with Tenzie's pushiness, but after Basil's estranged mother returns, his life is turned upside down . . . and Tenzie may be the only person to help him put it back together again.
Once again, MJ Auch has written a thoughtful coming-of-age novel that explores friendship, family, and fitting in, in One Plus One Equals Blue.