Han Xin pointed to the soldiers:
In Sun Tzu's Art of War more than a thousand years ago, there was such an arithmetic problem: "Today's events are unknown, and the number of three and three leaves two, the number of five and five leaves three, and the number of seven and seven leaves two. What is the geometry of things? " According to today's words: divide a number by 3 and 2, by 5 and 3, by 7 and 2, and find this number. This kind of problem, some people call it "Han Xin points soldiers". A kind of problem is formed, that is, the solution congruence in elementary number theory.