2. The basic method to solve the problem of sum and multiplication: take the decimal as 1, the large number is n times the decimal, the large number is n, and the two numbers * * * are n+ 1.
3. Basic quantitative relationship: decimal = and ÷(n+ 1), large number = decimal × multiple or sum-decimal = large number.
4. Example1:Class A and Class B have 160 books. There are three times as many books in Class A as in Class B. How many books are there in Class A and Class B? Analysis: From the title, we know that the number of books in Class B is small, so Class B is a decimal, accounting for 1, and Class A accounts for (3+ 1). B: 160÷(3+ 1)=40 (Ben) A: 160-40= 120 (Ben).
5. Knowing the difference between two numbers and the multiple relationship between the two numbers, finding these two numbers is called the difference multiple problem.
6. The basic method to solve the differential multiple problem is to set the decimal as 1. If the large number is n times the decimal number, we can know that the large number is n according to the quantitative relationship and the difference between the large number and the decimal number. That is to say, if we know what the n- 1 number is, we can find out what the 1 number is.
7. Basic quantitative relationship: decimal = difference ÷(n- 1) large number = decimal× n or large number = difference+decimal. Example 1: The price of a table is three times that of a chair. A table is more expensive than a chair, 60 yuan. How much are these tables and chairs? Analysis: The price difference between the table and the chair is 60. If the chair is regarded as a decimal, it accounts for 1 and the table accounts for 3- 1. According to the quantitative relationship, the price of the chair is 60÷(3- 1)=30 yuan. The price of the table is 30+60.