This rule is a common method to calculate decimals in our life. When we add up the numbers of units, tenths, hundredths and thousandths, if the sum is greater than or equal to 10, then we need to go up to 1.
Take 400 words as an example. For example, we have to calculate 29+54 now. First, one digit is 2+4=6, no problem, but the ten digit is 9+5= 14, so there is a problem. Because 14 is greater than 10, we need to go up to 1.
The principle of this law lies in the characteristics of decimal numbers. In decimal numbers, the weight of each bit is different. The weight of one digit is 1, the weight of ten digits is 10, the weight of hundreds digits is 100, and so on. When the sum of the digits of a certain bit is greater than or equal to 10, it means that we need to borrow the previous bit, and the weight of the borrowed bit is 10, so we need to add this borrowed bit to the result.
Methods of learning mathematics:
1, do a good preview: read in the unit preview to understand the learning content in the recent stage, read carefully in the classroom preview, pay attention to the formation process of knowledge, and record the difficult concepts, formulas and laws so as to listen to the class with questions.
2. Listen carefully: Listening should include listening, thinking and remembering. Listen to the ins and outs of the formation of knowledge, listen to the solutions and requirements of examples, and listen to the mathematical ideas and methods contained in them. Thinking, being good at association, analogy and induction, being brave in questioning, asking questions and making bold guesses. Remember, remember methods, skills, doubts, requirements, and pay attention.
3. Seriously solve the problem: classroom practice is the most timely and direct feedback. You must not miss them. Don't rush to finish your homework. Read your notebook first, review the learning content, deepen your understanding and strengthen your memory.
4, learn to sum up: Although there are many things about mathematics knowledge, as long as the knowledge points are sorted out, you can achieve a clear hierarchy and a clear outline. In the process of combing, if you encounter unclear problems, you need to turn over the books to study the concepts carefully to prevent conceptual errors.