Expert analysis: this problem is also a dark difference problem. Parents can guide their children to think in two ways. The first method: we can start with the number 1 and grasp the key words of the problem. Assuming that Xiaohua gave 1 to Xiao Fang, Xiaohua would have less 1 and Xiao Fang would have more 1, then the difference between two stamps would be 1+ 1=2 (sheets). And so on, 8+8= 16 (sheet) is the number of stamps that Xiaohua originally had more than Xiao Fang. The second method: hypothesis method. Grasping the keyword "as many", suppose that the number of stamps with the same number of two people is 8. Then, the number of stamps before Xiao Fang was 8-8=0 (sheet), while the number of stamps before Xiaohua was 8+8= 16 (sheet). In this case, it can be concluded that the original number of "Xiaohua" stamps is 16-0= 16 (pieces).
2. Dalin crosses 15 more than Xiaolin, Xiaoming crosses 6 more than Xiaolin, and Dalin crosses more than Xiaoming.
Expert analysis: there are two ways to think about this problem. Method 1: According to the meaning of the question, it can be concluded that Kobayashi is a relatively intermediate quantity. We can assume that Kobayashi did the 1 question, then Dalin did the 15 question more than he did, that is, Dalin did the 15+ 1= 16 (Dao) question, and similarly, Xiaoming did the 6+1. From this, we can get the question 16-7=9 (Tao), which is that Dalin has done more questions than Xiaoming. Method 2: Think of this problem as the relationship between inclusion and inclusion. Parents can draw simple icons to help their children understand. Similarly, Kobayashi is also an intermediate quantity. Kobayashi painted Dalin on the left and Xiaoming on the right. Then, Dalin has more 15 questions than Kobayashi, including 6 questions that Xiaoming did more than Kobayashi. Then using 15-6=9 (Tao) is not just that Dalin did 9 more questions than Xiaoming.
Xiaohua is 6 years old this year. Father said to Xiaohua, "When you are 10, I will be 40 years old." How old is dad this year?
Expert analysis: the key to this problem is to grasp a constant quantity, that is, the age gap between dad and Xiaohua will not change, which we can find with 40- 10=30 (years old). Then, knowing that Xiaohua is 6 years old this year, I asked my father this year's age, which is obtained by 6+30=36 (years old).
4. Thirty students signed up for interest groups. Among them, 26 people from the art group and 7 people from the calligraphy group/kloc-0 participated. How many people are there in both groups?
Expert analysis: This question examines the relationship between inclusion and inclusion. According to the conditions, it can be calculated that the total number of students participating in the art group and calligraphy group is 26+ 17=43 (people), which is 43-30= 13 (people) more than the total number of students participating in the interest group. This shows that the extra number must be the number of students who have participated in both the art group and the calligraphy group.
5. There are two baskets of apples, the first basket is 25 and the second basket is 19. How many apples are taken from the first basket and put in the second basket? The number of apples in the two baskets is equal?
Expert analysis: This problem is a typical dark difference problem. The key point of this problem is to grasp "as much as you pay", and at the same time, the number taken from the first basket is the same as the number added from the second basket. Then, first of all, we can calculate that the number of the first basket is 25- 19=6 (pieces) more than that of the second basket. Excluding these six apples, the number of apples left in the two baskets is equal, so we only need to divide the six apples into two equal parts, that is to say, take three apples from the 1 basket to the second basket, and the two baskets are the same. Parents are advised to start with small numbers in the guidance, help children start with teaching AIDS, sum up the rules and calculation methods, and then the problem of light and shade difference of large numbers will be solved.
6. Xiaoli has 18 pictures. After giving Xiaolong three pictures, the number of them is the same. How many pictures does Xiaolong have?
Expert analysis: This problem is also a dark one. According to the conditions, firstly, it can be concluded that the number of pictures of Xiaoli is 18-3= 15 (one) after Xiaoli gives Xiaolong three. 15 is the number of pictures after Xiaolong got three. Then, the question asked Xiaolong how many pictures he had. Grasping the word "original", you can get 15-3= 12 (Zhang).
7. Mom has to walk 3 kilometers from home to the factory. Once, she walked 2 kilometers to work, then went home to get a very important tool, and then went to the factory. How many kilometers did mom walk to work this time?
Expert analysis: Parents can help their children reproduce the scene and simulate the whole process with their children. At the same time, parents are required to draw line drawings and indicate numbers, both of which are indispensable. When children really understand the whole process, it will be very easy to answer this question. The correct answer to this question is 2+2+3=7 (km).
8. A bus travels from East Station to West Station. If this bus leaves from East Station, after 1 1, will it be at East Station or West Station?
Expert analysis: This question is a comprehensive application of parity knowledge. Many preschool children know that 1, 3, 5, 7, 9 is singular, and 2, 4, 6, 8, 10 is even, but children don't really understand the meaning of odd and even numbers. Parents can instruct their children to use chess pieces at home 1 65438+. 1 Bus goes to West Station, 1 is singular, and 1 1 is also singular, so 1 1 Bus goes to West Station after the bus.
It takes five minutes for a cat to eat a mouse, and five cats eat five mice of the same size at the same time. How many minutes does it take to finish eating?
Expert analysis: This is knowledge about time and common sense. Parents and children will perform once in the form of scene reproduction, and children will really understand. The correct answer to this question is that it takes five minutes for five cats to eat five mice of the same size at the same time.
Xiaoming and Liang Xiao want to buy the same book. Xiao Ming is short of 1 yuan 7 jiao, and Xiao Liang is short of 1 yuan 3 jiao. If they use their money to buy the book together, the money is just right. What's the price of this book? How much money did they each bring?
Expert analysis: this question examines the relationship between the whole and the part. Two people add up to just one book. It can also be understood that the money for buying books is distributed to two people. Xiao Ming participates, Xiao Liang participates, and Xiao Ming is short of 1 yuan 7, which means that Xiao Liang has exactly 1 yuan 7 and Xiao Liang lacks 1 yuan 3, which means that Xiao Ming has exactly 65438. The correct answer to this question is Xiaoming 1 yuan 3 jiao, and Liang Xiao 1 yuan 7 jiao. The price of this book is 3 yuan money.
1 1. There are 35 sugars. In the order of naughty-smile-tintin-winter and winter, everyone sends one at a time. Think about it. Who will get the last one?
Expert analysis: This question examines the problem of average score. It is impossible to divide 35 sweets among four people equally. For children with strong ability, parents can guide their children to draw candy in a row of four, so that children can divide the average part first and the rest in order. At the same time, parents of children with poor understanding ability can prepare a corresponding number of chess pieces or sticks for their children to put in their hands. It is not difficult to get the last candy by hands-on operation.
12. The naughty boy started to have money in 300 yuan, so he went to 56 yuan to buy books, 128 yuan to buy stationery. How much less money did naughty leave than before?
Expert analysis: this question examines the relationship between the whole and the part. The whole (original money) is divided into two parts, one part is used money, and the other part is the remaining money. Asking how much money is left is less than the whole, in fact, asking how much money is spent. So the correct answer to this question is 56+ 128= 184 (yuan).
13, a child divided one bag of apples and two bags. How many apples are there in this bag?
Expert analysis: this question should grasp the keyword "at least" and the key sentence "divide it into two more", which means that everyone will get two more if they divide at least one, so it is at least eight.
14. A 60-meter-long rope needs 10 meter for skipping rope and 10 meter for repairing volleyball net. How many meters is this rope missing?
Expert analysis: The key is to understand the meaning of the problem, not how many meters are left, but how many meters are missing. If you subtract 1 meter, you will lose 1 meter. If you subtract 20 meters from this problem, you will lose 20 meters.
15. The mall returned 28 TV sets. Some were sold, and there were eight left. How many TV sets have been sold?
Expert analysis: this problem should be considered from the overall and local perspectives. The 28 TV sets returned by the shopping mall are divided into two parts, one part is sold and the other part is the remaining 8 sets. Subtract the remaining 8 sets from the total to get 20 sets sold.
16, Xiaohu learned to write Chinese calligraphy. I wrote three on the first day, and then I wrote more 1 every day than the day before. How much did he write in four days?
Expert analysis: this problem is a difficult problem for first-grade children. The difficulty lies in not directly adding up the figures of four days, but guiding children to calculate the number of words every day step by step in order, and then calculating the sum of four days.
17, Xiaoyun is 8 years old. Grandma said, "I will be 62 years old when you are 12 years old." How old is grandma this year? Expert analysis: The key is to let children understand that grandma and Xiaoyun grew up at the same age, and to cultivate children's reverse reasoning ability, so as to inspire children that Xiaoyun will have too many teenagers when he grows to 12 years old. Ask grandma again and she will be 62 years old in four years. Will grandma be 62 years old this year?
18, what is the result of subtracting the least two digits from the least three digits and then subtracting the first digit? Expert analysis: first of all, we should guide children to understand the concept of numbers and ask them how many digits 325 is. Why three digits? Keep asking, what is the minimum sum of three digits? When children understand this concept, it is much easier to answer.
The above is 18' s exercise on mathematical thinking. I hope that children can practice more and study mathematics well to make mathematics easier.