Educational dictionary hours refer to the time unit of teaching. The time of a class is called a class hour. A class hour in primary and secondary schools in China is generally about 45 minutes, and a class hour in colleges and universities is about 50 minutes, which is also called "class hour". It is generally believed that both non-adult education and full-time university education are 45 minutes for a class. 45 minutes times 55 hours is 4 1.25 hours.