Answer: i belive he means his birthday is sad
Explanation:To Tammet, numbers have shapes, emotions have colors, and math is as easy as blinking. He can learn to speak a language fluently from scratch in a week and has a complusive need for order and routine.In "Born on a Blue Day: A Memoir of Aspergers and an Extraordinary Mind," Tammet lets readers in on how his mind works. Not only does "Born on a Blue Day" provide a a fascinating portrayl of a man with unique talents, it also offers insight into the power of the human brain.
( hope this helped)