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Ancient simple mathematics
The meaning of this question is: there are several items, I don't know how many. If you count three, there are still two left; If you count five, there are still three left. If you count seven, there are still two left. Q: How many pieces are there in this batch?

It becomes a pure mathematical problem: there is a number, the remainder 2 is divided by 3, the remainder 3 is divided by 5 and the remainder 2 is divided by 7. Find this number.

The question is simple: 2 divided by 3, 2 divided by 7, so 2 divided by 2 1, the least common multiple of 3 and 7, 2 divided by 2 1, we will think of 23 first; 23 is divisible by 5, so 23 is an answer to this question.

This problem is simple because dividing the remainder by 3 is the same as dividing it by 7. Without this particularity, the problem would not be so simple and much more interesting.

Let's change an example; Han Xin counted the number of soldiers in a group. There were two left in a group of three, three left in a group of five and four left in a group of seven. Q: How many soldiers are there in this team?

This topic is to find a positive number, so that it can divide the remainder 2 by 3, the remainder 3 by 5 and the remainder 4 by 7. The smaller the number, the better.

If some students have never been exposed to such questions, they can also use the method of experimental analysis to increase the conditions step by step and deduce the answers.

Hope to adopt! ! ! ! !