Xiao Lili took her little friend back to the room, and after a while, she turned out a book: "This is the fourth grade, and I haven't learned it yet." But I heard the master say that this is the book of eight or nine-year-old children, so take this. ”

Xiaoyu asked if it would be too difficult, I couldn't understand it at all?

Xiao Lili said that of course she couldn't read if she couldn't read, and she couldn't read it herself, but adults could understand it.

The three little guys came back with the book and put it in front of Xiang Bei.

Xiang Bei flipped through and told Chu that it was boring to write articles all day long, and that it was necessary to take a comprehensive test, and arithmetic was a basic ability. If you don't understand the elementary school questions, then you should go home and sell sweet potatoes.

As he spoke, Xiang Bei found a question and asked Chu how about taking pity on this?

Chu took a look at the textbook: "Chickens and rabbits are in the same cage, there are thirty-six heads, one hundred and two feet, ask for the number of chickens and rabbits?"

Chu took out the paper and counted: "Thirty-six heads, one hundred and twenty feet." That's thirty-six chickens and rabbits, right?"

Xiang Bei said that he was talking nonsense, the chicken and the rabbit are both the same head, of course thirty-six. The key is one hundred and twenty feet.

Chu asked with pity that there were no crippled chickens or crippled rabbits?

Xiang Bei said that the disabled are not used for exams, and those who are used for exams are elites, not disabled.

Chu pitifully bit the pen and thought about it and muttered: "I count them one by one, I estimate that there are no less than five chickens, then I count them one by one, starting with five chickens, five chickens are ten legs, there are one hundred and ten feet left, one hundred and ten feet If all the hundred and ten feet are four-legged rabbits, it is twenty-seven and a half, this is not right, you can't come out of half of them." That's six chickens, six chickens are twelve legs, and there are one hundred and five left, and no, one hundred and five can't get rid of a four-legged rabbit........"

Chu pity is not finished yet, Xiang Bei asked her to stop, so that the exam is over, this is really a very simple question, it can be regarded as sending them a score question, there are at least ten solutions.

Chu pity let him calculate and listen, what is a simple method?

Xiang Bei said: "The first method, assuming that it is all chickens, we ask for rabbits. That's one hundred and twenty feet, minus the seventy-two feet of all chickens, which is forty-eight feet. Forty-eight feet divided by the two feet of the rabbit and the chicken equals twenty-four rabbits. Then counting the chickens is thirty-six minus twenty-four, which is equal to twelve chickens. On the other hand, all rabbits are counted as chickens, that is, thirty-six rabbits, minus one hundred and two, and then divided by two, which equals twelve chickens, and thirty-six minus twelve equals twenty-four. These are the two most regular algorithms, understand?"

A group of people shook their heads, not understanding.

Xiang Bei was helpless: "Then I'll say another algorithm, which is to pity your elimination, but you can't count one by one." If you want to use the basic knowledge to eliminate it instantly, I won't talk about the instant, I'll disassemble the instant for you to listen to, how to achieve instant elimination, it definitely makes sense. ”

Xiang Bei explained to them that if the rabbit has four legs, then its final number can only be the last five numbers of zero, two, four, six and eight, and it cannot be an odd number. Half of the possibilities are eliminated at once.

And the first one is thirty-six, then find the top first, the total number of rabbits cannot exceed thirty, because there are one hundred and twenty feet in total, and more than thirty feet is too much, which anyone can figure out at once. This excludes the post-thirty generation.

Then exclude the homing interval as an integer, ten does not need to be counted, it is too small. It is impossible to be within twenty, and this is also clear when you think about it, because twenty rabbits only have eighty legs, so the remaining sixteen chickens are not enough to make up the remaining fifty feet.

In this way, twenty before twenty is excluded, and after thirty is thirty is excluded. That's an even number between twenty-two and twenty-eight. There are four numbers in total, and it is not troublesome to bring them in one by one, and it will not delay the exam time. This is the fastest method of elimination.

This method is theoretically unqualified, but it is correct to calculate it this way. Because the arithmetic of this world is at this level. They can't be expected to go to the equations.

Everyone understands this method, and Chu asked if it is the same as he did just now, is it right to calculate the result?

Xiang Bei is right, as long as the answer is correct. If you are not afraid of delaying the time to do other questions, then go and slowly break your fingers to calculate, this is right, and the rest will be over.

Chu said okay with pity, this question is reasonable. However, it is estimated that a lot of people will have to be killed, there is no ninety-nine multiplication table in this world, and it is difficult to multiply orally, and it is impossible to be like him to instantly eliminate only four numbers left.

Xiang Bei said yes, everyone has their own algorithms, and it's no problem for majors to only read literature and not practice martial arts. She was delayed by her practice.

Chu agreed with pity, he was delayed by the practice, after all, the Five Elements Tongtian is still a forbidden air martial artist, and it is not so easy to practice.

Chu pity borrowed the slope to get off the donkey, asked the second question, and then two math problems, math problems are very important.

Xiang Bei took the pen and smiled evilly: "I thought of a question that I was afraid of when I saw it when I was a child, and I was really confused by that kind of question." ”

Xiang Bei wrote: "The two sisters and brothers went to the town from home, and the elder sister could walk ten miles for one hour, and walked for five hours first. The younger brother rode a horse for an hour and fifty miles, and he could catch up with his sister in a few hours. ”

Chu said pitifully that it was simple, my sister walked fifty miles in five hours, and my brother caught up in one hour.

Xiang Bei said no, when the younger brother was chasing his sister, his sister was also moving forward, not waiting in place, so it was not an hour.

Chu pity understands, that is, a moment, there is no shorter unit of time.

Xiang Bei said too, there are no minutes here, and there is no way to calculate the specific number, so as long as it is more than one hour and three quarters of an hour, it can be regarded as reducing the difficulty, as long as you don't let your sister stand and wait, and don't obviously write the time for a long time.

Set this, Xiang Bei casually turned another question and wrote it down for him. That's three math problems.

Chu asked what kind of question to get again, why don't you copy more from this textbook, this textbook is so difficult, how can Xiao Lili learn it?

Xiao Lili pursed her lips and said that she had studied hard and that she would have more time to rest in the future.

Xiang Bei said that he would not do mathematics, and when the time came, draw a bearing on the test paper, disassemble it, and let them write the working principle of the bearing and where it is suitable to be used, which is the simplest physics knowledge.

Chu said with pity, this is the most difficult exam ever.

Xiang Bei said that it is not difficult, in his hometown, this is all for children. Tell Chu to take pity, come up with a few more similar questions, and then think of an essay question, don't have the test questions that have been prepared in the palace, find someone to leak it secretly, and then see who has made a cheat sheet according to those questions, and drive it out directly, and those who are not good will not deserve the exam.

Chu said pitifully that this trick is good, this trick is awesome, so he just did it. As for the topic of the real essay, it is simply about this war.

Xiang Bei said no, it is estimated that many people have guessed this question, and they must have been prepared. In another way that no one can think of, don't have this kind of almost consensus. Be able to activate the brain.

Chu asked what was written?

Xiang Bei replied: "If you want to have a vision for the future, let them write about the Heavenly Dragon King City in a hundred years." ”

Chu said coolly, this topic is too cool.