同余的理论是初等数论里的一个重要课题,它要解决的是如何确定一个同余式(或同余式组)的解的个数与解的方法。这里着重介绍一下一次同余式组的解法。一孙子定理我国古代的《孙子算经》(纪元前后)里提出并解决了“物不知数”问题:“今有物不知其数,三三数之剩二,五五数。 The theory of congruence is an important topic in elementary number theory. What it needs to solve is how to determine the number and solution of solutions to a congruence (or congruence group). Here I will focus on the solution to the once congruence group. A grandson Theorem In ancient China, the “grandchildren” (before and after the epoch) put forward and solved the “Improper thing” problem: "There is no such thing as the present, the number three or three is the second or fifth.