IRAS: Chapter 625

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Chapter 625 The Peking University math teacher also genuflects!


Evening, 8 PM.

Chenchen put down her pencil and held her workbook, then said, “Zhang Ye, I’ve finished my homework. I want to watch TV.”

Zhang Ye, who had been browsing Weibo all this while with a smile on his face, looked over when he heard her voice. He said, “Did you really finish your homework? Alright then, go and watch for a while.”

Chenchen grabbed the remote control and then went to turn on the television and sat down on the sofa. She switched channels until she found the channel airing a recent, popular local cartoon and sat there watching expressionlessly. This cartoon was not about some big bad wolf or little white bunny type of child-oriented cartoon. It was one that was targeted more at male teenagers and even men in their twenties. Because the premise of the cartoon was about wuxia, there were fighting and romance spun into it. So even for someone at Zhang Ye’s age, if he wasn’t too picky about it, he could watch it if he wanted to give it a try.

“Zhang Ye.”

“What now?”

“The new episode has finished airing.”

“Then that’s all you get to watch today.”

“I want to watch it from the start. Help me to do that.”

“Do it yourself.”

“I don’t know how, Zhang Ye. Do it for me.”

Zhang Ye could not take the nagging and forced himself to get out of bed to take the remote control to play back the episode from the beginning. Task completed.

Chenchen started watching her cartoon and did not bother Zhang Ye anymore.

Zhang Ye was happy and continued to nonchalantly interact with the netizens on Weibo. In a short period of time, those questions of his had also gone viral like the wondrous math problem from the afternoon. More and more Weibo users had gathered wave after wave to try the question, not believing that they could not solve it, vowing that they had to do so to differentiate their IQs from the primary school students.

“I’m here!”

“How many more minutes are there?”

“There’s still about five minutes left, hurry up!”

“I’ve solved one of the questions, but I don’t know if it’s the right answer.”

“Hurry, hurry, hurry, we’re almost out of time! Everyone, don’t give up, let’s draw on the wisdom of the masses and try together. If not, we can just copy that Peking University math teacher’s answer, but we must not let Zhang Ye have the last laugh!”


“Brothers and sisters, let’s attack!”

“Slay Teacher Zhang!”

Zhang Ye thought that this was really fun, and on top of that, his objectives were also met. He had started “Zhang Ye’s Classroom,” first, due to everyone’s request. Second, for fun. Third, it was because Zhang Ye noticed the situation was just right, so he used this chance to increase his popularity as well. He took every opportunity he saw that could help him increase his popularity as a celebrity. After all you could never have enough and there was really no need to nitpick on how to get more.

He had already risen up to B-list celebrity now, but to put it plainly, he was just the last place celebrity in the B-list rankings, the weakest one of all. Together with the person chasing him, Central TV’s Spring Festival Gala host Chen Ye—who was in the top spot of the C-list ranking, still eyeing to get his position back with a lot of news and updates—, it showed that he was not letting Zhang Ye have it easy. And so, Zhang Ye’s online math class this time would definitely play an important role in helping him pull away from Chen Ye in the popularity rankings. He had to firmly grab hold of his position in the B-list celebrity rankings.

In this world, the Celebrity Rankings Index was an aggregation of data from many outlets, like the search rankings of a celebrity on various websites, number of Weibo followers, number of screen appearances, comments, and reviews of works, etc. Combining all those data, a popularity score would be derived and thus rank the celebrities accordingly. Whether it was really an objective way of collecting data, Zhang Ye did not know, but he knew that the people of this world all depended and watched this Celebrity Rankings Index very closely and recognized it as the authoritative aggregator. As for why each tier of celebrity rankings had limited spots in them, Zhang Ye had already read up on the explanation given by the official website which said that people follow a limited number of public figures, as each person’s attention span was limited. For example, Xiaoming might like 20 celebrities, and to him, they all had a different ranking, some higher, others lower, some that he liked more than the others and also some that he would soon forget about. This was what was meant by a person’s attention span was limited. So when he suddenly notices and likes a new celebrity, then the celebrity that was ranked last in his mind would probably be forgotten. Unless there were some new works or news about them, Xiaoming was unlikely to ever pay attention to them anymore.

The people’s attention span was limited, there was only so much of the pie that celebrities could get.

—This was the official reason why the spots in the Celebrity Rankings Index were limited.

Of course, if the market expanded in the future, be it due to rural urbanization, a rise in living standards, or increased spiritual fulfillment of people—leading to an increase of people who used to be unconcerned with celebrities from the entertainment circle becoming concerned—then the pie would become bigger as well. When that happened, the authorities would also take it into consideration and update the design of the Celebrity Rankings Index. They would likely increase the number of spots available in each tier accordingly. However, such occurrences were rare, not even likely to happen once in two years, so it was pointless to depend on such events. Rather, it was safe to depend on yourself. Zhang Ye understood very clearly his plan and knew that it was a priority for him to stabilize his popularity score at this moment. As long as he could do that, then he could consider his next step to chase after the other big shots in the B-list. Otherwise, all that he had done so far would be for naught. But looking at the current situation, it seemed that the effects were far-reaching and had even over-fulfilled his objective.

It was time, the deadline was over.

It was time to announce the answers.

Zhang Ye posted on Weibo: “OK, question time is over. Those who have not submitted their answers yet, you have one more minute to do so.”

“It’s already been an hour?”


“Wait, wait, wait!”

“I’m almost done!”

“Just wait for a while more! Let me do a few more calculations!”

Zhang Ye’s colleague—the Peking University math teacher—also submitted his answer at the last moment. Suddenly, countless netizens went to look and copy his answers and used it as their own.

When Zhang Ye saw this, he dismissed it with a laugh. Then he began to give out the answers to the question one by one. Of course, he had to also include the explanation and solving process, as all these questions he had set were very tricky. If he did not do that and just gave an answer, the people who could not understand would not know why it would be the correct answer. They would not take it just like that, so Zhang Ye would have to help them to the end by giving the answer along with explanation.

The first question…

The second question…

The third question…

One by one the answers were revealed!

After everyone saw them, they fell over like ninepins!


“Oh god!”

“So that’s how it is!”

“It really turned out to be elementary math problems?”

“The question that needed us to count the closed loops has left me kneeling!”

“Damn, how could this question turn out to be so simple? I even f**king thought it has to do with permutations and combinations! What a rip-off! Teacher Zhang, you’re really too much of a rip-off!”


“I finally understand why Teacher Zhang has made so many enemies! Teacher Zhang, if you keep scamming people this way, you won’t be left with any friends soon! I’m gonna cry!”

“F**k! All the questions are such scams! They’re all so deceptive!”

When they saw the questions an hour ago, they were already cursing at their mothers, but when they saw the answers now and realized it was so simple, they felt even more aggrieved. They started throwing a tantrum as one by one everyone started cursing at Zhang Ye hoping that he would get constipation or step on a banana peel and slip! How on earth did he come up with so many extremely wondrous questions!?

“Who got them right?”

“Let’s see who got them right.”

“I got them wrong.”

“I got them wrong too.”

“The questions are really not difficult, but it was really too tricky!”

Many of those who had copied the Peking University math teacher’s answer had realized now that he had also gotten one of his answers wrong. It was the answer for the second question that asked to explain the pattern that the numbers were separated by.

1, 3, 7, 8—1st tone.

10—2nd tone.

5, 9—3rd tone.

2, 4, 6—4th tone.

This was a question that combined the testing of language and math!

The netizens were utterly defeated.

“Even a Peking University math teacher could not get them all right?”

“We were totally defeated with no survivors?”

“It really seems like no one got them all right at all!”

“We were really wiped out? Oh my god!”

Those Peking University Math Department scholars were also downed. None of them got all four questions correct. The most they had were three questions correct.

Yao Jiancai said: “I think it’s better that I just go to bed. When the answers were released, I realized that I could not even understand what two of the questions were asking when faced with the answers!”

Peking University’s Su Na: “I didn’t even get one…”

Big Saber Bro was the same. Fan Yingyun had only gotten one question correct. Zhang Ye knew about Big Saber Bro’s math standard. As a world-renowned hacker and someone who was proficient in programming and code cracking, her math standards shouldn’t be bad at all. With things like 010101, they often deal with binary, however having a good standard in math did not mean that they would be good at math problems. When it came to answering math questions, what was most important was the way they interpreted the question.

This was an outcome that Zhang Ye had predicted. The first question had already filtered out 90% of the people who took part, the second question continued to attack them, while those who could do the third question were already considered non-existent. Back in Zhang Ye’s previous world, when people saw these questions, they would be able to answer them almost immediately. But that was because most of those people had already seen the answers before, or had encountered the questions before, so they knew the trick to answering them. As such, a small group of people could solve the questions. However, it was different in this world. Everyone’s learning and mindset of testing over here were all considerably more traditional and rigid. They had never encountered such questions before, so they did not have the fundamentals or flexibility of thought to deal with them. Being wholly wiped out this way was not an unexpected outcome at all.

The people were utterly defeated!

Zhang Ye took home a flawless victory.

The Peking University math teacher stood forward to humbly say: “When I saw these questions, together with this afternoon’s question, I suddenly broke out in a cold sweat and couldn’t help but think about something. It’s lucky that the primary school test, secondary school exams, or even the national college entrance exams did not have Professor Zhang Ye taking part in the setting of papers. If that were the case, then without a doubt, it would be a total nightmare for those test and exam candidates!”

“That’s right!”

“Damn, I’m taking my national college entrance exam this year, please don’t scare me like that!”

“Surely that won’t happen, right? Please don’t ever look for Zhang Ye to set the exam papers! If this person set a paper, then the straight-A students from Peking University and Tsinghua University might not get more than 20 points. They might even end up with 0!”

The netizens were also shocked by this. Many of them were students. If someday they faced such questions in their exams, then it would really be unimaginable. And besides, not to forget that Zhang Ye had only posed these elementary math problems, if he really set a few junior high, high school, or university level questions, then wouldn’t that make everyone unable to do anything? Who would dare thump their chests and say for sure that they could answer Zhang Ye’s questions?

No one would dare do that!

Look at how the Peking University math teacher was left genuflecting in the face of these questions!

On Weibo, an authoritative person in the field of education was also attracted by these elementary math problems. He appeared and said: “After the answers to these questions were revealed, it showed that they were really not difficult at all in the first place, but the people who could really answer them correctly were just too few and far between! Zhang Ye’s brain is truly a treasure of the mathematics world. These exciting and wondrous questions have also taught the education world something today. I have a feeling that in future exams and tests, we might be headed towards this new direction of development. In the past, our tests and exams were too corrupt and obsoletely structured. They’re no longer able to keep up with the times. But Zhang Ye has now shown us a new direction that we could head towards!”

Chapter 625 The Peking University math teacher also genuflects!

Announcement Post for this chapter (BONUS QUESTION IN ANNOUNCEMENT POST)

Translator’s note: Some news update for everyone, I’ve started my Patreon, so you can check it out here

  1. Get up to 15 chapters of reading in advance! Please go check it out on my Patreon Page!


Zhang Ye’s Classroom:

1. Little Zhang is the owner of a shoe shop. A pair of shoes cost ¥20 to buy and sell for ¥30. A customer pays with a ¥50 bill, but as Little Zhang did not have any spare change, he takes the ¥50 to a neighboring shop to change for five ¥10 notes. Finally, he gives ¥20 of change to the customer. Later, when the neighboring shop discovers that the ¥50 note is counterfeit, Little Zhang has no choice but to pay them ¥50. All in all, how much money did Little Zhang lose?

2. From 1 to 10, these numbers have been divided into four groups:

1, 3, 7, 8;


5, 9;

2, 4, 6.

Please explain the pattern that was used to separate them into their groups.

3. 7111=0. 8809=6. 2172=0. 6666=4. 1111=0. 2222=0. 0000=4. 5555=0. 8193=3. 8096=5. 4398=3. 9475=1. 9038=4. 3148=2.

Derive the following:


4: This is a picture-based problem.

In the first row: The images below are aliens—followed by four pictures of organisms

In the second row: The images below are not aliens—followed by four pictures of organisms

In the third row: Please circle which of the following are aliens.

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54 thoughts on “IRAS: Chapter 625” - NO SPOILERS and NO CURSING

    1. I think it’s 100. He has to pay 50 to his neighbour, he gave 20 in change to the customer & there’s the price of the shoes (20 is cost of purchase while 30 is cost of sale).

      1. Look at transactions separately. With his neighbor he gave a fake bill worth 0 and later a real 50rmb bill, he received 5 10rmb bills (and probably the fake bill if he asked for it). Overall he lost and gained nothing here. So his only losses are on transactions with the customer: Zhang received the fake 50rmb bill and he gave 20rmb of change as well as the shoes which cost 20 to buy and selling of which should’ve earned him another 10rmb in profit. IMHO in this case unearned profits shouldn’t be counted as a loss, so his losses are 20rmb in money and 20rmb in shoes value for a total of 40.

        You could also say that Zhang got a valuable lesson in remembering to check for counterfeits totally worth the 40rmb he spent for it, so he lost nothing. 🙂

        As for the 3rd question, it is about the amount of “circles” so 2889=5. But the 2nd one I have no idea.

  1. 1st: 90. Shoe costs 20 to buy. He gave 20 to the customer since 50-30(cost to sell) and the 50 to the neighbor owner

    2nd: no answer yet

    3rd: count the circles. 2889 has 5

    4th: I dont really know. it’s really weird.

    1. 1st – you forgot he also received 5 10rmb bills from neighbor. so he lost nothing there and losses are 40rmb.
      4th clearly can’t be solved without the pictures.

  2. I suspect that 4th is as following:

    First one: no
    Second one: Alien
    Third one:no
    Fourth one: no
    Fith one:Alien

    I won’t even botehr about the rest xD

    1. I just noticed the among the non-aliens from the ( the images below ar not aliens) the 1st is a pig and the 4th is a bird. the 2nd a vacuum…?

      and for the answer….I dunno but the 5th one is definitly not an alien and is either a chicken or a school bus 🙂

    1. I believe you’re right lol. Because the second line says “below are not aliens”.
      Where as the last line says “circle the aliens”

  3. As other people have mentioned.
    1. seems to be 40 when all transactions are separated
    3. is 5 when the numbers are switched to their equivalents. First find what is zero automatically like 7, 1, 2, and 5, then find what is 1 like 6 and 0, then find the difference between 8809 and 8096 being 6 and 5 respectively, concluding that 8 is 2 and 9 is 1, so 2889 =5 .
    4. I suspect that the fourth from the left is an alien. These problems deal with similarities in one group that aren’t shared in another. At first I thought that all the aliens had three antenna, but some non-aliens do too. Then I added on that the aliens had 3 antenna and a triangle on the body. None of the non-aliens have boths traits. Lo and behold, the fourth organism has these traits too.

    1. The 4th question, i think the only NON ALIEN one is the last one (the 5th one), because all of the other share a similarity (triangle) just like the samples.

    2. You seemed to complicate the matter a lot. Q3 only count the holes in the number, primary school students (those who under grade 5) did not deal with 3 digit number yet, and the question is primarily deal with all primary students so it must be restricted on primary skill: Count. And also they will choose the easiest path: count the holes in the number.
      For answer to Number 4, check my answer (which is waiting for mod approval)

    3. I’m thinking the 4th the answer is actually none of the images are aliens as the question states “the images below are not aliens” meaning the problem isn’t actually a maths problem but rather a question comprehension problem.

  4. 1.70 value of shoe+20¥ change another 20¥ to give the neighbor to make the 50¥.

    2. 1,3,7,8 school idols
    10 is a loner
    5,9 the school bullies
    2,4,6 3 clowns

    3. 5. Yep 2889 have 5 circles

    4.all are aliens to me.

  5. Now that there’s a picture, here’s my answer for the 4th question: only the 4th from the left (2nd from the right) is an alien, because all aliens have a triangle in them and 3 “balls on wire” sticking out of them.

    PS How did Zhang Ye draw something like that in a few minutes and on his phone no less. Just unbelievable.

      1. Yeah you’re probably right. I just thought it’s strange to include a picture question in here as it’s much harder to replicate from memory than just typing some text messages. Personally I don’t think I could copy that picture and upload it in less than 30-60 minutes even with the original right in front of my eyes.

        1. Time capsules bro, remember, he can perfectly remember certain things from his life to the point of almost photographic memory. That, and memorizing things has always been his specialty. Now, as to whether he would be willing to waste a time capsule on something as trivial as this, I don’t know.

  6. 1. 40 RMB: HE received 50 and pay back 50, no loss here. He lost 20 rmb for the shoe and 20 rmb for the change + Energy he used to ran to neighbor’s store :)))

    2. Count them out loud in Chinese, you’ll see. Or follow this dummies guide:

    3. Number of holes: 2889 = 5

    4. Turn 180 the image, the one who smile to you is not alien, the one who angry towards you/have malicious look (eg sample alien number 5) is alien. => Answer is 1 and 2

  7. 1. 40 RMB: HE received 50 and pay back 50, no loss here. He lost 20 rmb for the shoe and 20 rmb for the change + Energy he used to ran to neighbor’s store :)))

    2. Count them out loud in Chinese, you’ll see. Or follow any Chinese counting guides on Google

    3. Number of holes: 2889 = 5

    4. Turn 180 the image, the one who smile to you is not alien, the one who angry towards you/have malicious look (eg sample alien number 5) is alien. => Answer is 1 and 2 (You can also check @chk reply because it also restricted the main point of question to counting)

    1. You’re definitely on to something about the 2nd question, too bad my chinese is limited to “ni hao”. But in the 4th question I don’t really see a difference e.g. between the smiles of the 1st alien and 1st non alien no matter how I turn my screen.

      1. The proportion of kid’s drawing is needed to be considered in this problem: there’s no neck and body, so the hands and feets are connected to the face. And also we need to look for the “real face” of the drawing.
        For non-alien 1 look from the botton, is he smiling to you? For alien 1, assume the triangle is the eye and the other is lost, does he look like a villian?
        Welp bc my answer is vague and based on imagination too much, @chk answer may be the correct one (triangle with 3 balls stick out is the alien, there for organism number 4)

  8. 1) 40 rmb loss…
    2) don’t know yet but someone said the sound of that number in chinese
    3) 5 (number of circle)
    4) NONE in 3rd row are alien… why?
    Below first sentence is alien…
    (First row image)
    Then it reach new clasification…
    Below second sentence is NOT alien…
    (Second row image)
    And the third sentence did not give new clasification… so it still NOT alien… and ALL third row is NOT alien.

  9. 1. He gifted customer 50 RMB + 50 RMB for counterfeit = 100
    2. dunno, i think it’s essence was lost in english
    3. 2889 = 5 circles
    4. huh, is it question??? just bunch of alliens, all of them are ALIENS!!!!! Zhang Ye too is ALIEN!!! WHAT SORT OF QUESTION IS THAT!!!

    1. I was rash…
      1. 10 RMB profit, customer sells him shoes(30 RMB) and he gives him 20 RMB (50 RMB – 20 RMB = 30 RMB), then gives neighbor 50 RMB ========== 10 RMB
      30 + 30 – 50 = 10 RMB, there are not mentioned about selling or buying so i was confused(ZHAN YE, YOU EVILDOER!!!), hahahaha….. haha … haaaaa………

  10. 1. Shoe 20 + change 20 = so maybe 40

    2. I think it about sound like
    1,3,7,8 = yi1, san1, qi1, ba1
    10 = shi2
    5, 9 = wu3, jiu3
    2, 4, 6 = er4, si4, liu4

    3. 2889 = 5

    4. I think only picture no 4 from left

  11. 1. I didn’t get for sure but I say 40.
    2. This one deals with the Chinese way to say numbers so I can’t do it.
    3. 5.
    4. I’m pretty sure the simplest answer is 0. The question states that only those in the 1st row are aliens and none of those in the 3rd row match. So…

  12. i think most of the answers are already mentioned by the time i read up to here.
    but ill still give it a try

    1. [shoe cost (-20) , shoe and change (-20)+(-20)] = -60 , neighbor (+30 -50) …
    therefore, -20 -20 + (30-50) = -80 SHE LOST 80
    same situation,
    she spent (-20) on a shoe, someone stole her shoe(-20) and (-20) RMB.
    Neighbor gives her (+30) and ask back (-50) total she lost 80!!!!!

    2. following the (4 tones of Chinese) at which the numbers are said in Chinese

    3. 2889 = 5 (yes, i count the holes)

    4. this one is rigged. Answer cant be blank, so ill go with the 3 antenna and a triangle. SO 4th one, you are the alien

  13. 1. $50 for the fake bill (to the neighboring shop), $20 for the shoes (to the customer) and $20 for the change (to the customer): $90
    2. Dunno, but whatever the chapter said 🙂
    3. 2889 = 5, because you’re counting circles in the number shapes.
    4. Not sure, but 4th, since he’s the only one who follows the pattern in row one.

  14. Apparently the answer to the alien pictures is 5. (so 5th alien or all 5?)
    Why? Cause in Chinese the question literally has the answer 5 behind it. And this hasn’t been translated over in English.

    So… I found a site that’s talking about this math question including the original picture.
    If anyone can properly translate it (I just used google translate) and you can tell me what exactly it says.

  15. 1. he didnt loose. he won 10 from the sale. about the fake 50 it was worth nothing to begin with so he just got 50 and gave them back
    2. following the (4 tones of Chinese) at which the numbers are said in Chinese
    3. 5 circles
    4. the word “below” means none of the pictures on the third row are alians

    i copied the last 3 answers from some people above

  16. 1: 50Y and 4: only alien from those five at botttom line is 4th as he is only one with 3antennas. and triangle, 3: 5holes but that was answered multiple times and groups dont have time to check those sounds 😀

  17. I see a lot of people insisting that it is 40rmb….even though many fellows posted the correct answer 90rmb.
    Imagine that the buyer actually didn’t pay anything(just gave a piece of worthless paper):
    The owner lost the pair of shoes 20rmb,lost the change he gave for free along with the shoes 20rmb and lost the 50rmb bill he payed back to the neighboring shop in total 90rmb.The fake bill does not count as money….
    It is an elementary class problem so it is assumed the guy is lawful,will not use further the fake bill.
    For the same reason the answer shouldn’t be 70rmb(the “actual money” lost,since the 20rmb of the shoes is just the value of the shoes,the shoes not being actual money).An elementary class question wouldn’t play tricks with semantics.
    Superb novel,nice chapter! Thank you for your hard work Legge and team!

  18. it’s 40. got 50 from his neighbor. gave 20 as change and the shoes(shoes were 20 for him to get) was the result of the transaction. but his loss was only the 20 for him to get the shoes in stock, the change was from neighbors money, not his own. after giving 20 as change he has 30/50 left. then he had to return the money to neighbor, had to add in 20 out of his own pocket. only the shoes and the money he had to add to return neighbors money was his loss. thus he only had 40rmb in losses.

    think of it this way. u selling a drink for $3. it cost $2 to make. customer give fake $5, u go ask change from friend for $5. and give customer $2 as change and have $3 left over from ur friend. but the bill was fake. you u lost $2 of ur own from cost to make the drink. and ur friend only get $3 back. so ur losses here is $2 so far. but ur friend still missing $2 so u have to give him another $2. and there u lost $4 in total from cost to make drink and paying ur friend back $2.

  19. What a fun brain teaser chapter.

    Here’s my answer without looking ahead or other comments:

    1. 90 yuan. (20y for shoes lost + 20y change to customer + 50y to compensate the other shopkeeper)

    2. I don’t know why the chapter said “tone”, but my answer is that each group is separated by a new line. So:
    1, 3, 7, 8; = 1st line
    10; = 2nd line
    5, 9; = 3rd line
    2, 4, 6. = 4th line

    3. 2889 = 2889 (ignoring the above 7111=0. 8809=6. 2172=0. 6666=4 etc answers bc they’re all wrong and can’t do math!)

    4. Circle nothing! (Because only the dudes in the first line are aliens! The dudes in the 2nd and 3rd line can’t be aliens bc the 2nd line said nothing below are aliens!)

    I’ll chk out the answering next chapter. I had a blast trying to figure everything out haha.

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