I don t know how to solve a problem of rotating numbers

Solution: (1) From the title: the three-digit number 3a4 is divisible by 2, the three-digit number a43 is divisible by 3, and the three-digit number 43a is divisible by 4.

According to the divisible property, the sum of a+4+3 is divisible by 3, so a can only take 2, 5 or 8. Only the three-digit number 43a is divisible by 4 when a is taken as 2. Therefore a=2

2) From the title: the three-digit number 2bc is divisible by 3, the three-digit number bc2 is divisible by 4, and the three-digit number c2b is divisible by 5. According to the three-digit number c2b is divisible by 5, so b can only take 0 or 5.

However, b in the three-digit BC2 cannot be taken as 0, so b = 5And according to the divisible property, the sum of 2+b+c is divisible by 3, so c can only take 2, 5 or 8. Finally, there is a three-digit number bc2 that is divisible by 4.

Hence the three-digit number 255

There is an n-digit natural number, a1a2a3....The pullability of an-2an-1an is divisible by m, and the new number a2a3 obtained by rotating the digits in turn....The pull-energy of an-2an-1ana1 is divisible by m+1 ......As shown in Figure 1If the three-digit number 3a4 is a "rotation number" of 2, then a=? 2.

If the three-digit number 2bc is a "rotation number" of 3, then the three-digit number is?

Mathematize the question first:

If the large, medium and small boxes are ABC respectively, then:

20a+15b+10c=1000 000

i.e. 4a + 3b + 2c = 200 000

and a (a+b+c) 2, i.e., a b+c

b (a+b+c) 3, i.e. 2b a+c

Of course, when two inequalities are equal signs, the total number of boxes used is the least. Replace and take an equal sign:

a=b+c④

2b=a+c⑤

Substitute :

4(b+c)+3b+2c=200 000

7b+6c=200 000⑥

2b=b+c+c

b = 2c ba substitution: 7 2c + 6c = 200 00014c + 6c = 200 000

20c=200 000

c=10 000

Substitution: b=2c=2 10 000=20 000Substitution: a=b+c=20 000+10 000=30 000Total number of boxes = a+b+c

60,000 = 60,000.

Definitely minus points, because there is still a gap with the correct answer, mathematics pays attention to steps and results, and if one of them is missing, it should be subtracted, especially in junior high and high school, and it is more concerned about the steps, subtracting points is minus, but the minus is not a lot, it should be one-third.

A unary equation is fine, and there is no need to set three variables of xyz.

Let the total number of boxes be x, first meet the maximum box to the maximum limit, i.e., 1 2x, then the medium box to the limit, i.e., 1 3x, and the rest is the number of small boxes, (1-1 2-1 3)x=1 6x

20*1/2x+15*1/3x+10*1/6x=1000*1000x=60000

Let the total number of boxes be x, because at least try to use large boxes and medium boxes, according to the most, x 2 for large boxes, x 3 for medium boxes, x x 2-x 3 = x 6 for small boxes, 1000 tons = 1000000 kg, column equation.

x 2) 20+(x 3) 15+(x 6) 10=1000000 to get x=60000

Set x for large boxes, y for medium boxes, and z for small boxes, with 20x 15y 10z 1000 1000. To make x y z as small as possible, x,y should be as large as possible (due to the large x,y coefficients). Since x is not more than half of the sum and y is not more than one-third of the sum, then x takes half of the sum and y takes one-third of the sum, and the above equation can be solved by substituting the above equation to get x 30000, y 20000, z 10000, x y z 60000.

The system of equations 20x+15y+10z=1000, x is less than 1 2(x+y+z), z is less than 1 3(x+y+z) solve it yourself, I'm not sure.

Set the total number of boxes to x, because to bai is less, so try to use large du boxes and medium boxes, according to the most zhi count, large boxes with x 2, medium dao boxes with zhuanx 3, small boxes with x-x 2-x 3 = x 6, 1000 tons = 1,000,000 kg, column equation.

x/2)×20+(x/3)×15+(x/6)×10=1000000

Solution x=60000

Don't waste time, do other questions immediately, and when you are done, come back immediately, and then use your brain to analyze this question, so as not to delay the time to complete the homework, and it is an exam, and you should do it like this. Otherwise, it will affect the effect of other questions. In this case, you must do the other questions first, and then slowly ponder after the other questions are completed.

If there is a question that you can't do, then give it up, because as long as you take most of my questions, answer them all correctly, and ensure the correct rate, then it is enough. If you keep sticking to that one question, it will delay time and reduce the accuracy of other questions. Therefore, when it is time to give up, you must know how to make trade-offs.

Do you mean when it comes to exams? Then don't waste time, skip this question first, do the other questions first, and when you are done, come back immediately, and then use your brain to analyze this question, so as not to delay the completion of the exam. And maybe after doing other problems, you will think of a way to do this problem.

After reading your question, I would like to share with you the order of doing the question: from front to back, first easy and then difficult, steady and steady, and finally tackle the problem.

We are likely to encounter some obscure questions or problems in the exam, which should be predictable in advance, and should be fully psychologically prepared, but to think about it this way, if you feel that it is difficult to do or will not do it all at once, it is very likely that others will also be difficult to do, so don't panic, you can skip this question first, and when the other questions are basically done, then go back and correct your thinking and then do it.

This is in terms of the score situation.

If it's an exam, I won't do it.

should be put aside first, and the questions that will be done should be completed first, so as not to affect the mood and cause greater mistakes, and then have time to think about the questions that will not be done.

If you want to complete your homework, try to think independently if your time allows, but if you can't do it, ask for help from others.

If you are doing the exercises on your own, then think about it for a while, and if you don't have an idea, go to the activity, rest and rest, let the brain relax and be clear, and then think about it after a while, maybe there will be different results.

The general choice is to look at the score and difficulty, if the score is relatively high and there is a certain possibility to overcome, then you can spend some time trying, if the basic steps are completed first, get some points. If you choose the last two questions of the fill-in-the-blank questions, then you can first let go and finish the questions that can get points as long as you have time, and then go back and deal with them slowly. If the conditions do not allow, you can only get an answer, and don't leave it blank.

Hang it first and do the questions that will be done, and then study the questions that will not be done when they are done, so that you can arrange the time reasonably to answer the questions, in case there is a situation that is too late, first easy and then difficult, don't be in a hurry if you can't do it, keep a good attitude and take your time.

If you don't know how to do the questions, you can ask the teacher or students who are better at learning, and complete it under the guidance of teachers and classmates, and it will not be difficult to do the problem next time you encounter internal vision.

I advise you to do the rest of the work first, it is meaningless, the exam is also the pursuit of efficiency, to have a sense of the overall situation, otherwise you will waste time, but what you will do is not done or even have time to read, isn't it a pity? In the future, the boss will not say that you will be asked to do another thing after you finish one thing, but there may be several things to do at the same time, and then you should consider that thing first, and you can't say that you will spend time on one thing before you finish it.

Learn from the past. Review the previous knowledge carefully, think carefully, and ask for help.

What should I do if I find that I can't do a question?

The workarounds are:

1. You can choose to ask your teacher or classmates, or you can find the answer online. Understand its solution and put it in the notebook so that you don't make the same mistake the next time you encounter a similar problem. It's best if you practice this type of question a little more.

Second, you can choose to think seriously and independently. Exercise your thinking skills and thinking skills. Maybe "the mountains and rivers are full of doubts, and the willows and flowers are bright and another village". Believing that you can do it, self-confidence is also a kind of courage to do problems.

3. You can choose to skip this question, write the following question, and then slowly come back to this question. Maybe you will be inspired by the following questions, and then when you come back to do this problem, you may have a good idea.

Generally speaking, when you encounter a problem, you must think about it carefully, and if you really can't, you must understand it. You can't pretend to understand. If you encounter a math problem, you must understand its solution ideas and methods, master his solution ideas and methods, and you can easily solve similar problems.

When taking the exam, you must pay attention to the allocation of time, do not waste more time on small questions, you can skip it for the time being, and you can make up for it later if you have the inspiration to do the questions, and the time for the big questions is vacant within ten minutes, clarify your thoughts and answer the questions quickly.

Usually encounter a question that you can't know, you must check and fill in the gaps in time, ask friends, teachers, classmates are okay, be sure to take notes, remember to say thank you to the person who asks, the help of others is not a matter of course, and grateful people often have good luck.

This kind of thing is taught from a young age, skip first, try to finish everything you know, and then go all out to overcome that problem, you don't have to worry about other problems, and you don't have to worry about anything else, so you will deal with the problem with a relaxed mind, and sometimes it will be very rewarding.

If you find that there is a question that you can't do in the book you are doing, in fact, this is also very simple, you can sit in the back first, and then finish the next question, and then you can slowly think about this question or ask someone else who understands, so you can, you don't have to be so troublesome, always stay on this question.

Put him down to do other questions first, and then do this question at the end, so that you won't lose time and won't affect your ability to do the questions.

Can you first imagine what is the knowledge point of this question? Think about reading the textbook to effectively grasp the knowledge points of this problem, and at the same time, you can also calm down first, and then be able to find a good idea to solve this problem.

If it's an exam, then put it to the end. If it's a normal day, ask a classmate or teacher.

It depends on when and on what occasion. When you take the exam, let it go first, pick the simple ones and do it first, and if you still have time, don't get into the horns. Usually do homework to do a representative problem first, check the information, ask others for advice as soon as possible, the problem is completed, if you are relieved, and then do other questions is easy.

Two paths, one to give up, and one to the end.

If you are in the exam and the time is not very sufficient, you can do this question after completing the rest. If you have enough time and you have to solve it, you can ask some teachers or people with strong professionalism.

Think patiently and see if it's easy to see if it's easy, and then calm down.

Adjust the cell in the valence: e2=if(d2<50,round(d2*,2),d2).

New total price cell: h2=round(e2*f2,2).

E2 input formula =if(d2<50,round(d2*,2),"")

This means that if the unit price is less than 50 (not including 50), the result is, i.e., **10%, and rounded to two decimal places, greater than or equal to 50, the result is empty. If you adjust the price to have ** in each box, change the formula to =if(d2<50,round(d2*,2),d2)

G2 or enter =if(e2<> in H2"",round(e2*f2,2),round(d2*f2,2))

This also means that if the value of e2 is not empty, the calculation result is the adjustment price * cargo volume, rounded to two decimal places, if not, it is the original price * cargo volume, rounded to two decimal places.

If you use the second formula for the cell of e2, then the cell of g2 can be changed to =round(e2*f2,2).