Ethereum shares candy on January 19
Publish: 2021-04-22 03:10:26
2. How many students are there? According to this algorithm is divided into four, more than 19, divided into five, more than one, then there are a total of 18 students.
3. 21
4. 1 to x,
2 to x-15,
3 to x-9,
(x-15)+(x-9)=48,
2x-24=48
x=36
2 to x-15,
3 to x-9,
(x-15)+(x-9)=48,
2x-24=48
x=36
5. 25, the ratio is 50:50:25
6. If x candies are set, then x + 1 can be divided into 5, 6 and 7. The minimum is 5 * 6 * 7-1 = 210-1 = 209
7. Suppose there are n children. Then the last child will get n candies and the remaining one seventh. There is nothing left by now. That one seventh is zero. Then the last kid he got was (n-1) × 1 + one seventh. That's n minus one plus one seventh. There are n on both sides, and they are equal. So one is one seventh. Then he had six out of seven. seven × 6 / 7. Everyone gets six candies. There are six children in all.
8. There are 18 students,
19-1 = 18< There are 91 candies in total,
19 × 5+1=91
primary school mathematics problem-solving methods and skills
mathematics in primary and secondary schools, including Mathematical Olympiad, requires appropriate methods in learning. With good methods and ideas, you may get twice the result with half the effort! What methods can be used? I hope you can use these thinking and methods to solve problems
image thinking method refers to the method that people use image thinking to understand and solve problems. Its thinking foundation is the concrete image, and the thinking process from the concrete image
the main means of thinking in images are material objects, graphics, tables and typical materials. It is characterized by indivial performance in general, always retaining the intuitive nature of things. Its thinking process includes representation, analogy, association and imagination. Its thinking quality is manifested in the active imagination of intuitive materials, the processing and refining of the image, and then prompt the essence, the law, or the object. Its thinking goal is to solve practical problems, and improve their thinking ability in solving problems
physical demonstration method
use the physical objects around to demonstrate the conditions and problems of mathematical problems, and the relationship between conditions and conditions, conditions and problems. On this basis, analyze and think, and seek solutions to problems
this method can visualize the mathematical content and make the quantitative relationship concrete. For example: encounter problem in mathematics. Through the physical demonstration, we can not only solve such terms as "at the same time, facing each other and meeting", but also point out the thinking direction for students
in the second grade mathematics textbook, "three children shake hands when they meet, once for every two people, several times in total" and "how many double digits can be placed with three different digital cards". Such knowledge about arrangement and combination, in primary school teaching, if the method of physical demonstration, it is difficult to achieve the expected teaching objectives
especially some mathematical concepts, if there is no physical demonstration, primary school students can not really master. The area of rectangle, the understanding of cuboid and the volume of cylinder all depend on the physical demonstration as the basis of thinking
Graphic Method
with the help of intuitive graphics to determine the direction of thinking, find ideas, and find solutions to problems
the graphic method is intuitive and reliable, easy to analyze the relationship between number and shape, not limited by logical derivation, flexible and open-minded, but the graphic relies on the reliability of people's image processing, once the graphic does not conform to the actual situation, it is easy to make the association, imagination on this basis appear wrong or go wrong, and finally lead to wrong results
in classroom teaching, we should use more graphic methods to solve problems. Some topics come out with pictures, and the results come out; Some questions, the picture is good, the topic meaning student also understood; Some problems, drawing can help to analyze the meaning of the problem, enlighten ideas, as an auxiliary means of other solutions
list method
list method is used to analyze, think, find ideas and solve problems. The list method is clear, easy to analyze and compare, prompt rules, and is also concive to memory
its limitations lie in its small scope of solution and narrow types of questions, which are mostly related to finding or displaying rules. For example, the teaching of positive and negative proportion, data arrangement, multiplication formula, digit order and so on, mostly adopts the "list method"
verification method
is your result correct? We can't just wait for the teacher's judgment. The important thing is to have a clear mind and a clear evaluation of our own learning, which is the essential learning quality of excellent students
verification method has a wide range of applications and is a basic skill to master. Through practical training and long-term experience accumulation, we should constantly improve our verification ability and graally develop the good habit of being rigorous and meticulous
(1) verification with different methods. It is repeatedly put forward in textbooks that subtraction is tested by addition, addition by subtraction, division by multiplication and multiplication by division< (2) substitution test. Is the result of solving the equation correct? Use the substitution method to see if both sides of the equal sign are equal. The results can also be used as conditions for reverse calculation
(3) whether it is in line with the reality“ Tao Xing's words should be implemented in teaching. For example, it takes 4 meters of cloth to make a suit, and the existing cloth is 31 meters. How many sets of clothes can be made? Some students do this: 31 ÷ 4 ≈ 8 (sets)
it is undoubtedly correct to keep the approximate number according to the "rounding method", but it is not consistent with the reality, and the remaining cloth can only be discarded. In teaching, we should pay attention to common sense. To make an approximate calculation of the number of sets of clothes, we should use the "tailing method"
(4) the power of verification lies in conjecture and doubt. Newton once said: "without a bold guess, we can't make a great discovery."“ Guessing is also an important strategy to solve the problem. It can open up students' thinking and stimulate the desire of "I want to learn". In order to avoid guessing, we must learn to verify. Verify whether the guess results are correct and meet the requirements. If it does not meet the requirements, adjust the conjecture in time until the problem is solved.
19-1 = 18< There are 91 candies in total,
19 × 5+1=91
primary school mathematics problem-solving methods and skills
mathematics in primary and secondary schools, including Mathematical Olympiad, requires appropriate methods in learning. With good methods and ideas, you may get twice the result with half the effort! What methods can be used? I hope you can use these thinking and methods to solve problems
image thinking method refers to the method that people use image thinking to understand and solve problems. Its thinking foundation is the concrete image, and the thinking process from the concrete image
the main means of thinking in images are material objects, graphics, tables and typical materials. It is characterized by indivial performance in general, always retaining the intuitive nature of things. Its thinking process includes representation, analogy, association and imagination. Its thinking quality is manifested in the active imagination of intuitive materials, the processing and refining of the image, and then prompt the essence, the law, or the object. Its thinking goal is to solve practical problems, and improve their thinking ability in solving problems
physical demonstration method
use the physical objects around to demonstrate the conditions and problems of mathematical problems, and the relationship between conditions and conditions, conditions and problems. On this basis, analyze and think, and seek solutions to problems
this method can visualize the mathematical content and make the quantitative relationship concrete. For example: encounter problem in mathematics. Through the physical demonstration, we can not only solve such terms as "at the same time, facing each other and meeting", but also point out the thinking direction for students
in the second grade mathematics textbook, "three children shake hands when they meet, once for every two people, several times in total" and "how many double digits can be placed with three different digital cards". Such knowledge about arrangement and combination, in primary school teaching, if the method of physical demonstration, it is difficult to achieve the expected teaching objectives
especially some mathematical concepts, if there is no physical demonstration, primary school students can not really master. The area of rectangle, the understanding of cuboid and the volume of cylinder all depend on the physical demonstration as the basis of thinking
Graphic Method
with the help of intuitive graphics to determine the direction of thinking, find ideas, and find solutions to problems
the graphic method is intuitive and reliable, easy to analyze the relationship between number and shape, not limited by logical derivation, flexible and open-minded, but the graphic relies on the reliability of people's image processing, once the graphic does not conform to the actual situation, it is easy to make the association, imagination on this basis appear wrong or go wrong, and finally lead to wrong results
in classroom teaching, we should use more graphic methods to solve problems. Some topics come out with pictures, and the results come out; Some questions, the picture is good, the topic meaning student also understood; Some problems, drawing can help to analyze the meaning of the problem, enlighten ideas, as an auxiliary means of other solutions
list method
list method is used to analyze, think, find ideas and solve problems. The list method is clear, easy to analyze and compare, prompt rules, and is also concive to memory
its limitations lie in its small scope of solution and narrow types of questions, which are mostly related to finding or displaying rules. For example, the teaching of positive and negative proportion, data arrangement, multiplication formula, digit order and so on, mostly adopts the "list method"
verification method
is your result correct? We can't just wait for the teacher's judgment. The important thing is to have a clear mind and a clear evaluation of our own learning, which is the essential learning quality of excellent students
verification method has a wide range of applications and is a basic skill to master. Through practical training and long-term experience accumulation, we should constantly improve our verification ability and graally develop the good habit of being rigorous and meticulous
(1) verification with different methods. It is repeatedly put forward in textbooks that subtraction is tested by addition, addition by subtraction, division by multiplication and multiplication by division< (2) substitution test. Is the result of solving the equation correct? Use the substitution method to see if both sides of the equal sign are equal. The results can also be used as conditions for reverse calculation
(3) whether it is in line with the reality“ Tao Xing's words should be implemented in teaching. For example, it takes 4 meters of cloth to make a suit, and the existing cloth is 31 meters. How many sets of clothes can be made? Some students do this: 31 ÷ 4 ≈ 8 (sets)
it is undoubtedly correct to keep the approximate number according to the "rounding method", but it is not consistent with the reality, and the remaining cloth can only be discarded. In teaching, we should pay attention to common sense. To make an approximate calculation of the number of sets of clothes, we should use the "tailing method"
(4) the power of verification lies in conjecture and doubt. Newton once said: "without a bold guess, we can't make a great discovery."“ Guessing is also an important strategy to solve the problem. It can open up students' thinking and stimulate the desire of "I want to learn". In order to avoid guessing, we must learn to verify. Verify whether the guess results are correct and meet the requirements. If it does not meet the requirements, adjust the conjecture in time until the problem is solved.
9. 9+6=15
15 ÷ 5-4) = 15 children
two questions
16 × 3=48
48 ÷ 16—10)"= 8
8 * 10 = 80 sugars
15 ÷ 5-4) = 15 children
two questions
16 × 3=48
48 ÷ 16—10)"= 8
8 * 10 = 80 sugars
10. 1. Suppose the number of candy is x, the number of children is y
y = 2x + 16
4x = y + 20, y = 4x-20
2x + 16 = 4x-20
2x = 36, x = 18
18 children, 52 pieces of candy
2.
3x = 5Y
4 (x + 10) = 5 (y + 10) 4x = 5Y + 10
x = 10, y = 6
Xiaogang is 10 years old and Xiaofang is 6 years old
y = 2x + 16
4x = y + 20, y = 4x-20
2x + 16 = 4x-20
2x = 36, x = 18
18 children, 52 pieces of candy
2.
3x = 5Y
4 (x + 10) = 5 (y + 10) 4x = 5Y + 10
x = 10, y = 6
Xiaogang is 10 years old and Xiaofang is 6 years old
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