The teaching of decimal order should be carried out after understanding the meaning and counting unit of decimals. It should be understood that decimals are the same as integers, the ratio between every two adjacent units is ten, and the ratio between integer 1 and two counting units of ten is ten. Correctly grasp the numerical order of decimals, so as to pave the way for the teaching of correctly reading and writing decimals and new knowledge.

In the teaching of decimal reading and writing, we should make full use of the existing knowledge and introduce new decimal reading and writing methods from the known reading and writing methods of two decimal places. Decimals are extended from integers, so integer knowledge will have two transfer effects on decimal knowledge learning.

One is positive migration, such as the decimal value principle and decimal relation of integers, which can promote the learning of decimals. Second, negative transfer, such as the comparison of decimal size, number names, pronunciation and writing methods, will be disturbed by the mindset of integer knowledge. It is necessary to strengthen comparison and make full use of the existing integer knowledge to learn decimals.

For example, the decimal part is read as an integer, and the decimal part can be read in turn according to the number on each digit. In practice, in addition to the exercises in the book, similar topics can be supplemented to deepen students' understanding of the meaning of decimals from all angles. For example, give some decimals between 0 and 1; What do the three 5s in 5.525 mean?

Basic properties of decimals:

Add or delete 0 at the end of the decimal, the size of the decimal remains the same, but the counting unit changes. Moreover, if the decimal point is moved one, two or three places to the left, the original number will be reduced by 10 times, 100 times and 1000 times; if the decimal point is moved one, two or three places to the right, the original number will be expanded by 10 times and 100 times.