When talking about cyclic decimals, students get the concept of cyclic decimals by calculating 400÷75: the decimal part of a number starts from a certain place and one or several numbers appear repeatedly in turn. Such decimals are called cyclic decimals. I asked a question: How to express the cyclic decimal? By guiding students to combine Chinese symbols, you can use ellipsis to represent …, so write 5.333…

It can be seen that omitting three points is not a mistake in textbook arrangement. What makes textbooks sometimes omit at six points and sometimes at three points? Compared with the above figure, it is not difficult to find that the three-point ellipsis is generally used in numbers, symbols and enumerations. In Teacher Yang's book Standardization of Omission in Sci-tech Books and Periodicals, several situations of three-point ellipsis are summarized:

1. Omit numbers or symbols

2. Ellipsis in the formula

3. The formula is omitted.