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Hello, children. I’m your teacher Yi. Let’s learn the double insertion problem together today. [1.9 seconds] let’s take a look at the topic first. After moving the decimal point of a number to the right by one digit, the number obtained is 108 more than the original number. What is the original number? After reading it, don’t worry about the formula. Let’s analyze the topic first. [1.9 seconds] what does it mean to move the decimal point of a number one digit to the right? Is to expand this number by 10 times. [1.9 seconds] how is it represented by a graph? We can use a circle to represent the original number, so how many circles to represent the expanded number? [1.9 seconds] Yes, we use 10 circles. The number obtained is 108 more than the original number, [1.9 seconds]. In the figure, we can see that this is the extra part, that is, this part is 108. And this part has 10 minus 1 circle, that is to say, the number represented by these 9 circles is 108, so what is the number represented by a circle? We can list the formula: [1.1 seconds] 108 divided by 10 minus 1, and the final result is equal to 12 In other words, the original number was 12 Is it very simple? Let’s try a problem! [1.1 seconds] look at the title. [1.1 seconds] the sum of a and B is 803. After moving the decimal point of a to the left, the number obtained is equal to B. What are the numbers of a and B respectively? [1.1 seconds] similarly, through the drawing method, we can get the following formula: [1.1 seconds] number B: 803 divided by 10 plus 1 equals 73, [1.1 seconds] number A: 73 times 10 equals 730 or 803 minus 73 equals 730. Children, have you learned? [1.1 seconds] that’s all for today. Bye.