2 can be divided into 1 and 1, 3 can … 6 can be divided into 1 and 5, 2 and 4, 3 and 3 … and so on …

Let students have a basic understanding of numbers.

Numbers originated from ancient people's counting, and later knots were invented. In the 3rd century, ancient Indians invented numbers. In the 7th and 8th centuries, the empire established by Arabs rose, and the number of people spread to the west. Therefore, people later got used to treating city numbers as Arabic numerals. Basic Arabic numerals include 0, 1...9 and so on.