Given the 100 students in the Springdale High School senior class,38 students are taking math,45 students are taking psychology,and 12 students are taking both classes.How many students in the senior class are taking exactly one of the two classes?
问题描述：
Given the 100 students in the Springdale High School senior class,38 students are taking math,45 students are taking psychology,and 12 students are taking both classes.How many students in the senior class are taking exactly one of the two classes?
答
不用阶乘啊…… 第一位不能用0、1，所以有8种组合。后面6位每位有10种组合，一共是8*10^6=8,000,000
答
题目大概意思为,有100名学生,其中选修数学的有38名,选修心理学的有45名,选修所有课程的有12名，问这个班里各选其中之一的有多少人？
答
38-12+45-12=59
答
71