Left Primary and Secondary School 5th Grade Language and Mathematics League Mathematics Paper

Original = 1-1 2+1 2-1 3+1 3-1 4....1/99-1/100=1-1/100=99/100。That is, the use of split terms to eliminate.

Categorical mathematical ideas are important. This question has to be looked at separately

First of all, we must understand the meaning of the original expression.

2 represents case one: the two represent a whole number or case two: 2 multiplied

The same is true for 3 Consider it the same way.

If it is case 1, then there is: 2*()3*()=410 +4*()=380 "Note: () represents 10 to the nth power".

There is no solution in the range of real numbers (as a fifth grade, you don't need to understand the concept of real and imaginary numbers, just write no solution) If it is case two, the answer is like what most people say:

3 = 410 -- equation

4 = 380 -- equation

Multiply both sides of the formula by 2 at the same time, get: 2 +8 = 760 -- equation 3 subtract both sides of the formula on both sides, get: 5 = 350 so, =70 substitute =70 into the formula, get 2 +210 = 410 so =100, that is, at this time =100, =70.

Not counted. There is no solution in the range of real numbers.

So if you're in the fifth grade, you just don't exist.

If 2 means 20+ or 200+, then there is no solution to this problem as follows!

2)-(1) De.

2*10~n+10~n=-20

10 n is the nth power of 10, obviously there is no solution, of course n is an integer and if 2 means 2* then they all give the answer.

However, the meaning of this question example is the first one.

2★+3☆=410 ①

Equation 2- Equation.

Substitute the formula into the formula.

So the solution.

Through everyone's answers, I saw a certain sadness, a certain sadness of education. I don't think the fifth-grade children have been exposed to the so-called binary equations and the so-called classification and discussion ideas.

If there is no contact, do you think a fifth-grade child can understand everyone's problem-solving ideas? If I do, I can't help but feel sorry for our current children.

The relationship between stars and numbers is not multiplication.

There is no solution.

2 +3 = 410 -- equation

4 = 380 -- equation

Multiply both sides of the formula by 2 at the same time to get: 2 +8 = 760 -- the formula subtracts both sides of the formula on both sides respectively, and obtains: 5 = 350 So, =70 substitutes =70 into the formula, and gets 2 +210 = 410 so =100

So the answer is: =100 =70

Let's go into detail about this.

Adopt me put.

For example: 23 + 36 = 410 i.e. 2 (100) + 3 (70) = 410 Note: (100) + 4 (70) = 380

Note: 3+46=380

3 is 100

6 means 70

Solution: 2 +3 =410 --formula +4 =380 --formula

De: Right = 410-380 = 30

So: left = 2 + 3 - (4 ) = 30 i.e. (2 - 3 -4 ) = 30

2&-1*=30 （ "*"are strings of several "0s") after observation, the left "&"."*"Regardless of the number of "0" strings, the highest digit of the subtracted quotient is "1", which is not equal to 30

There is no solution to the original question.

No solution It can't be 2 digits.

Is it multiplication? The example you gave is not it.

Let's see the example.

It's an equation! ★=100

No solution. 2★+3☆=410

It can be divided into 20+ +30+ = 410

So there is no solution.

I don't know if the first question is written incorrectly

2 questions and 3 questions. 4 questions 5 questions The last number should be written incorrectly The last one should be.

Is there only 2 parentheses? Which = Which one to fill in?

Write out the original question and tell me, I'll help you.

1) Among the girls in this group, (5) achieved good results, and (4) did not achieve good results.

2) The best score is 42 per minute and the worst score is 12 per minute.

Good luck with your studies!!

In the sit-up test conducted by the school for fifth-grade girls, it is good to do more than 22 per minute, and the number of more than 22 is expressed as a positive number, and the number of less than 22 is expressed as a plural number. The results of the 10 girls in the first group are as follows (unit: one):

1) Of the girls in this group, (5) achieved good results, (5) did not achieve good results (2), the best score was 42 per minute, and the worst score was 12 per minute.

The "complex" number should be a "negative" number.

Solution: Let this number be x, according to the title:

x=16A: ......

Hello: Point card 304

Set to x x 16

If you don't understand, you can ask!

Let this number be x

x=3/32

So this number is 3 32

Just write it with your heart.

First, write about some of the difficulties you have encountered in life, and then write about how you are and how you solve them.

Then just write a simple ending.

That's what I wrote anyway.

I'm also in 6th grade.

I'm writing a simple calculation.

For example (this is what I wrote):

Easy way to calculate.

In every exam, you basically have to take the calculation, and the students must be tired of calculation, especially the four mixed operations, plus fractions and decimals, which is really annoying. However, after all, the exam is to test the calculation, so how to make the calculation less annoying and not easy to make mistakes? Then you need to use the law of simple calculation.

Common laws of simple calculation are: the commutative law of addition a+b=b+a, the associative law of addition a+b+c=a+(b+c) and other laws.

For example, the following question is the one that appeared in our three trainings:

If this question is calculated vertically, it will be very troublesome, and it may also be miscalculated. If you want to calculate it simply, you can split it into 100+, and then you can use the multiplicative distributive property to calculate it easily:

This makes the calculations much easier, no more dead calculations, and less prone to errors.

In calculations, although you can use formulas, there are some problems that need to be calculated step by step, for example, there are two sets of four operations that are easy to fool: 12 48 12 48 and 12 48 (12 48). The first one seems to be quick to calculate, but in fact, it's just a trap, and if you have to do a simple calculation on the first one, you can also offset it with 12 and 12 to convert it into 48 48.

The order of operation of the second is the opposite of the first, first calculate the 12 48 in parentheses, and then calculate the previous 12 48 according to the order of operation, which can be converted into 1 1 The result is equal to 1.

Calculations, it's hard to see, in fact, as long as you use some laws of operation, they are like magicians, making calculations easy. Therefore, mathematics is very wonderful, as long as you study and think hard, no matter how difficult the math problem will be solved. I wish you progress in your studies!!

Auntie's math problems.

My mom opened a stationery store, and today is a Sunday, and my mom has something to do and asked me to go to the store. After a while, an aunt came, and she said that she had to test me before she could tell me what to buy, and she said, "Li Hui bought a pencil and an exercise book, and it cost a total of yuan."

An exercise book costs twice as much as a pencil. How much do pencils and exercise books cost? I thought about it:

The exercise book and the pencil are three times in total, as long as you use it, you can find the pencil's **, and the exercise book's ** can also be found. I said the answer, and my aunt praised me: "It's good to be able to analyze the question carefully!"

I want to buy 10 copies of each exercise book and give you the yuan, no need to look for it, how many exercise books should you give me, how many copies of the text? I thought for a while and said, "Let's assume that 10 books are all texts, and you need 10 yuan, and you actually pay yuan, which is less than the assumption, and the actual texts are more diverse than the exercise books, then you can find that the exercise books are books, and the texts are 10-3=7 books."

I figured it out, my aunt praised me for being smart, I was happy in my heart, and then my aunt bought a few kinds of stationery, and I was still immersed in joy when I checked out, but I miscalculated the money, I didn't find out, but my aunt said to me: "You, you will get carried away when you praise you." I misread the decimal point of the money I should have paid, and as a result, I paid less.

I'm sorry, the decimal point has moved one place to the left, 10 times smaller than the original **, a difference of 9 times, as long as the yuan, because it was reduced by 10 times just now, so I want the yuan. "Auntie bought a few more stationery and left.

"Easily Ignored Answers".

There are many interesting things in the world, and there are many interesting things in our kingdom of mathematics. For example, in my current workbook for Book 9, there is a question that goes like this: "A passenger car travels 45 kilometers per hour from Dongcheng to Xicheng, and after traveling for an hour, it stops, and then it is exactly 18 kilometers away from the midpoint of the east and west cities, how many kilometers are the distance between the east and west cities?"

When Wang Xing and Xiaoying solved the above problem, the calculation method and result were different. The kilometers calculated by Wang Xing were less than those calculated by Xiaoying, but Mr. Xu said that the results of both were correct. Why is that?

Did you come up with it? You can also calculate the results of the two of them. Actually, we can quickly make a way to solve this problem, that is:

45 km), km), km), but if you look closely, you don't feel right. In fact, here we ignore a very important condition, that is, the word "away" in the condition "at this time is just 18 kilometers away from the midpoint of the East and West Cities", does not say that it has not reached the midpoint, or has exceeded the midpoint. If it is less than 18 kilometers from the midpoint, the column formula is the previous one, and if it is more than 18 kilometers from the midpoint, the column formula should be 45 kilometers), kilometers), kilometers).

So the correct answer should be: 45 km), km), km) and 45km), km), km). Two answers, that is to say, Wang Xing's answer plus Xiaoying's answer is comprehensive.

In daily learning, there are often many math questions with multiple answers, which are easy to be ignored in exercises or exams, which requires us to carefully review the questions, awaken life experience, carefully scrutinize, and fully and correctly understand the meaning of the questions. Otherwise, it is easy to ignore the other answers and make the mistake of generalizing.

Today, my mom and I went to buy light bulbs. When I arrived at the supermarket, I found that there were two kinds of light bulbs in the supermarket: one was an energy-saving bulb and the other was an ordinary bulb.

Although energy-saving bulbs only need one kilowatt-hour of electricity for 200 hours, 170 hours more than one kilowatt-hour of ordinary bulbs, it costs 5 yuan for one; An ordinary light bulb costs only 1 yuan, which is 4 yuan cheaper than an energy-saving bulb, but it takes one kilowatt-hour of electricity for 30 hours.

My mother asked me, "If I want to buy a light bulb to go home, which one is the most cost-effective?" ”

I thought about it for a while, and then said unhurriedly, "It can be counted like this:."

30 5 = 150 (hours) 200 hours "150 hours can also be counted like this:

200 5 = 40 (hours) 30 hours < 40 hours From these steps, it can be concluded that energy-saving bulbs save money. ”

Mom asked me again, "Good." Think about it again, is there any other way to do it? ”

I thought about it for a while, and then I said, word by word, "Can it be a percentage?" Count. ”

It can also be counted like this:

Or so it goes:

Therefore, it is also cheaper to save energy bulbs. ”

My mom and I bought a more cost-effective energy-saving light bulb and went back.

From this incident, I learned that "there is mathematics everywhere in life".

Interesting profession.

Xiao Zhao, Xiao Ding, and Xiao Zhang are teachers, doctors, and lawyers, respectively, and they only know: 1. Xiao Zhao is older than teachers; 2. Xiao Zhang and the teacher are not the same age; 3 Xiao Zhao and the lawyer are friends, can you deduce who is the teacher, who is the lawyer, and who is the doctor?

According to the fact that 1 Xiao Zhao is older than the teacher and 3 Xiao Zhao and the lawyer are friends, it can be inferred that Xiao Zhao is neither a teacher nor a lawyer, so Xiao Zhao is a doctor, and then according to the fact that 2 Xiao Zhang and the teacher are different years and Xiao Zhao is a doctor, it can be seen that Xiao Zhang is a lawyer, so the rest of Xiao Ding is a teacher.

This question is very simple, I used the method of elimination, for example: according to conditions 1 and 3, it can be seen that Xiao Zhao is neither a teacher nor a lawyer. The answer can be found by analogy.

In the process of learning mathematics, as long as we master the methods, we can solve all problems, and we can't imagine that we can also have fun from mathematics.

There are x number of people in the fifth grade who participate in the math competition.

310-x）×3/8=x×2/5

15（310-x）=16x

16x+15x=310×15

31x=310×15

x=310×15÷31

x=150A: There are 150 students in the fifth grade who participate in the math competition.