Numbers were a mystery to me. I was so far behind. It was only in Nairobi, at age ten, that I figured out anything at all about the way time is calculated: minutes, hours, years. In Saudi Arabia the calendar had been Islamic, based on lunar months; Ethiopia maintained an ancient solar calendar. The year was written 1399 in Saudi Arabia, 1972 in Ethiopia, and 1980 in Kenya and everywhere else. In Ethiopia we even had a different clock: sunrise was called one o'clock and noon was called six. (Even within Kenya, people used two systems for telling time, the British and the Swahili.) The months, the days--everything was conceived differently. Only in Juja Road Primary school did I begin to figure out what people meant when they referred to precise dates and times. Grandma never learned to tell time at all. All her life, noon was when shadows were short, and your age was measured by rainy seasons. She got by perfectly well with her system.