Keywords: mysterious and wonderful primary school grade one
This article applies to: the first grade of primary school.
Composition source:
This composition (600 words) is about the first grade of primary school (600 words). The title is "Wonderful Mathematical Mystery". Everyone is welcome to contribute.
What should I do with this problem? Yes, yes ... What a small head! Turn it up! Well, I have to ask my mother. It's like this: a piece of grass grows at a high speed every day. This kind of grass can feed 27 cows for 6 weeks or 23 cows for 9 weeks. So how many weeks can this grassland feed 2 1 cow? After reading the question, my mother patiently told me: "The number of grass in this lawn is changing every day. The key to solve the problem should be to find the invariant-the original grass number. Because the total amount of grass can be divided into two parts: the original grass and the newly grown grass. Although the newly grown grass changes, it should be noted that it grows at a constant speed, so the number of newly grown grass in this grassland is unchanged every day.
Suppose a cow eats one serving of grass a week, then 27 cows need to eat 27× 26 = 162 (serving) for six weeks, and eat both new grass and original grass; 23 cows need to eat 23× 9 = 207 (servings) in 9 weeks, and the new grass and the original grass are also eaten. And 162 is the sum of the original number of grasses and the number of newly grown grasses within six weeks; 207 copies are the sum of the number of original grass and the number of new long grass in nine weeks, so the number of new long grass per week is: (207-162) ÷ (9-6) =15 (copies), so the number of original grass is: 162-65438. Grass grows 15 times a week on this grassland, which is equivalent to arranging 15 cows to eat newly grown grass, so this grassland can feed 2 1 1 cow 72 ÷ (21-0/5) =12.
In the new semester, a new atmosphere, the travel train to explore the mysteries of mathematics is entering the sixth grade, the last big station of primary school. From here, you will enter the magical and charming mathematics kingdom. You will know new friends such as fractional division, fractional multiplication, fractional mixed operation and negative numbers, and you will use them to solve new problems in your life, improve your ability to analyze and solve problems and improve your learning quality. Circle, graphic conversion, location determination and other old friends will meet you again.
During this journey, you will make new friends and meet old friends again. You will gain more systematic mathematical knowledge, encounter more complicated mathematical problems and have more flexible methods and strategies to solve them.
Students, I believe we will experience innovation, appreciate success, share happiness and thrive in our new life!
Attachment: Very interested, thanks to the beautiful dividing line.