Math diary, Grade Five, Book One, Knowledge Arrangement of Fractional Multiplication
Fractional multiplication has two concepts. What can be reduced must be reduced first, and the product is 1, and the two numbers are reciprocal. I also know something about fractional multiplication: understand the significance of fractional multiplication, master the calculation rules of fractional multiplication, and calculate correctly. Using the method of transfer analogy to study and summarize, it has good ability of analysis, thinking and questioning. The meaning of multiplying a fraction by an integer is based on the meaning of integer multiplication "a simple operation to find the sum of several identical addends". The derivation of the calculation rule of multiplying fractions by integers needs to start with the addition of fractions with the same denominator, so the calculation rule of adding fractions with the same denominator is also the basis. In addition, in order to simplify the calculation, what can be reduced in decimal multiplication is reduced first and then multiplied. So finding the common divisor and reduction of two numbers is also an important knowledge base. This part of knowledge is closely related to the old knowledge and can be learned through migration. You can ask a few questions to do when reviewing. At the same time, we should also summarize the significance of integer multiplication: integer multiplication refers to the simple operation of finding the sum of several identical addends, which is also the significance of multiplying fractions by integers and is a very important basic knowledge. After that, two fractions with the same denominator are added by calculation. Then let's talk about the understanding of the formula; The meaning of the formula is actually easy to understand: what is the score of a number? With the knowledge of integer multiplying fraction as the foundation, I will learn the example of multiplying fraction by fraction more easily. On this basis, I can try to sum up the meaning of multiplying a number by a fraction myself.