How much does the subject need? The new teaching design shows that the key to oral arithmetic teaching is to let students understand oral arithmetic. For grade three students, intuitive method is the best way to understand arithmetic. According to students' learning situation and age characteristics, the teaching design of this section is as follows: 1. Understand the arithmetic of various methods of multiplying two digits by one digit. The arithmetic of multiplying two digits by one digit is to divide the whole into blocks and then sum these products. In teaching, in order to highlight this algorithm, we use RMB model, partition diagram, list calculation and other methods to visually present the "block quadrature" link, so that students can thoroughly understand this algorithm and effectively guide their own calculations. 2. Give students enough space to explore. Students' autonomous learning is an effective means to improve learning efficiency and an important way to cultivate students' interest in learning. In teaching, students are provided with enough time and space to cooperate and communicate, explore independently, find solutions to problems, experience the fun and sense of accomplishment in learning mathematics, and learn from each other's thinking results. Pre-class preparation teacher preparation: PPT courseware learning test card student preparation: train of thought diagram and blank form RMB model teaching process teacher guidance student activity effect test 1. Review old knowledge and introduce new lessons. (5 minutes) 1. Do the math. 30× 3 = 400× 4 = 5× 60 = 7× 200 = 2. Talk about the calculation method of integer ten and integer one hundred times one digit. 3. reveal the topic. 1. Look at the topic, think independently, and calculate the numbers by mouth. 2. Describe the calculation method of integer ten and integer one hundred times one digit. 3. Be clear about what you will learn. 1. Fill it in. (1)35 has () tens and () ones. (2) The number consisting of eight ones and eight tens is (). ③ There are four () and six () in 46. Second, explore new knowledge. (20 minutes) 1. The courseware shows the situation map of 32 pages of the textbook. How much does it cost to buy three swimming rings? Question: What mathematical information do you need to know to solve this problem? 2. Formulating independently and trying to calculate. Thinking: Is this formula the multiplication we have learned? Is there any way for you to work out its number? 3. Organize students to communicate and show their own calculation methods. 4. Show the calculation process: multiply the ten digits and the single digits of an integer by one digit respectively, and then add the two products, namely 10× 3 = 30, 2× 3 = 6, 30+6 = 36. Organize students to operate and understand with RMB model. 5. Understand the calculation method of naughty smiling face. (1) The calculation method of showing naughty smiling faces in courseware. (2) Ask students to combine ideas and tables to talk about the problem-solving ideas of naughty and smiling. Thinking: How are naughty and smiling calculated respectively? (3) Find out the similarities and differences between the two methods. (4) Organize students to demonstrate the calculation methods of naughty and smiling with tables and bitmap respectively. 6. Consolidate the exercises. The courseware shows 32 pages of examples in the textbook. The price of kayaking is four times that of rubber balls. How much is a kayak? 7. Organize students to exchange and show. 8. Organize students to summarize the calculation method of multiplying two digits by one digit. 1. Observe the situation diagram and get the mathematical information presented in the diagram. 2. Clarity: figuring out how much to buy three swimming rings means figuring out how much to buy three swimming rings 12. Calculated by multiplication, the formula is 12×3. This formula is two digits multiplied by one digit, which needs to be converted into a learned formula for calculation. 3. Communicate in groups and tell your own calculation process and ideas. 4. Understand the calculation process and put out three 12 yuan according to the meaning of the formula. Then point out which part of the above figure 10× 3 = 30, 2× 3 = 6 and 30+6 = 36 respectively. 5. Observe and understand the calculation method of naughty smiling face. (1) Observing the calculation method of the naughty boy, we can know that the naughty boy divides 12 into two sixes on average, multiplies the two sixes by three respectively, and then adds the two products. (2) Obviously, Xiaoxiao is calculated with tables. Take 12 as 10+2, then multiply 10 and 2 by 3 respectively, and finally add the two products. (3) Observing the calculation methods of naughty and smiling, it is obvious that the same point is to block the whole and get the sum of these products; The difference is that when the whole block is divided, it can be equally divided or unequally divided. (4) Hands-on operation: first demonstrate the calculation method of naughty and smiling as it is, and then try to demonstrate the calculation method of smiling by dot diagram and demonstrate the calculation method of naughty with tables. 6. Think independently, list formulas and try to split the bitmap or solve problems with tables. 7. Present their own calculation processes and talk about their own ideas. 8. Check the calculation process. Summary: When two digits are multiplied by one digit, you can first divide the two digits into an integer ten and a digit, then multiply them by another multiplier respectively, and finally add the products of the two multiplications. 2. Fill in the blanks. (1) When calculating 13×3, you can first regard 13 as ()+(), then multiply it by () respectively, and finally add the two together (). (2) Write the calculation process of 16×4. () × () = () × () = ()+() = (3) The product of the largest single digit and the smallest two digits is (). (4) The product of the largest single digit and the largest two digits is (). 3. Complete the form below. Unit price/yuan 15 32 45 quantity 3 pieces 3 pieces 2 total price/yuan 4. Use the table to calculate the following questions. Solve the problem. Carp: 14 yuan per kilogram of herring: 10 yuan per kilogram of 9 yuan cod (1) How much does it cost to buy 5 kilograms of cod? (2) Mom bought 2 Jin of cod, 1 Jin of herring. How much did it cost? (3) Please ask another math question and answer it. Third, consolidate and improve. (10 minutes) 1. Use intuitive consolidation calculation method. Complete the question 1 on page 33 of the textbook. Thinking: How much and how much can the two digits in the formula be divided into? 2. Complete the two questions on page 33 of the textbook. 1. Observe the bitmap and RMB diagram, think about how to circle your own calculation ideas, and then work it out. 2. First, get effective mathematical information from the chart, then think independently, calculate in the form of columns, and finally exchange and modify collectively. 6. Correct your mistakes. Fourth, the whole class summarizes. (5 minutes) 1. What did we learn in this class? What calculation methods have you learned? 2. Arrange the learning content after class. Talk about your gains in this class. How much does it cost for the teacher to annotate the blackboard design? The price of kayaking is four times that of rubber balls. How much is a kayak? 18× 4 = 72 (yuan) Method 1: 10× 4 = 408× 4 = 3240+32=72 Method 2: 40+32=72 Method 3: 2× 4 = 88× 9 = 72 A: canoe 72 yuan.