The years of welding at Hogwarts

"So in a situation like this, how do you tell whether an answer is correct?"

The eagle head on the door knocker opened its mouth but made no sound. It looked thoughtful, as if it had fallen into a state of thinking after being left speechless by Noah's question.

"As far as I know, Muggles generally call this type of pure text questions with multiple answers subjective questions. In addition to subjective questions, there are also objective questions."

At this point, Noah revealed his true colors. “Generally speaking, the most common objective questions are math problems.”

The knocker was silent for a few seconds. "But simple math calculations cannot reflect a student's intelligence."

"Simple?" Noah sneered contemptuously, "Who said math problems are simple?"

He gave an example of a door knocker.

Example: A solid has the circle x^2+y^2≤1 as its base, and all the cross sections of the solid perpendicular to the x-axis are squares. Find the volume of the solid.

Is this a math problem?

The knocker had an eagle head with a confused expression on it.

Looking at the door knocker with circles in its eyes, Noah revealed a wicked smile as if he had succeeded in his evil plan.

He sat down at the door of the lounge and said, "I just happened to have some time. Let me tell you what advanced mathematics is."

Fortunately, even though such a long time has passed, perhaps because of the two time travels, the memories of Noah's previous two lives are still clearly presented in Noah's mind as if they were engraved on his soul.

Even some memories that had long been forgotten were found back.

For example, when he was preparing for the postgraduate entrance examination, he watched Teacher Tang’s mathematics class on Bilibili.

More than an hour later, a slight sound of footsteps was heard in the distance, gradually approaching the direction of the Ravenclaw common room.

"It's getting late."

Nuo Ya climbed up swiftly, brushed off the dust on his clothes, and quickly moved his legs which were numb from sitting cross-legged.

"I'm going to go back now. I'll come back to discuss math problems with you when I have time. It was a pleasant chat today."

The knocker politely responded, "See you next time."

His figure disappeared out the window.

Before leaving, he did not forget to close the door of the common room for the Ravenclaw student who had obviously just returned from a night out.

Chapter 45 Everything was fine when I came here, alas, I can't go back

Early Wednesday morning, Noah appeared in the Great Hall of Hogwarts with light dark circles under his eyes.

It has been less than three days since the start of school, and the students have spent a total of three nights in Hogwarts, and some have already stayed up all night for three nights in a row.

All I can say is that he is worthy of being an immortal cultivator who traveled across time from the East.

Sitting at the Slytherin table, Noah couldn't stop glancing in the direction of the Ravenclaw table, an action that aroused Snape's murderous intent.

Don't get me wrong, he wasn't looking at Shirley.

He was just looking at the little eagles who were unaware of the impending disaster.

At the Ravenclaw table, several students had dark circles under their eyes that were obviously worse than Noah's. They looked as if their bodies were drained after fighting all night.

"Roger, why do you look like you have kidney deficiency?"

"You guy, I'm afraid your girlfriend drained your body last night, didn't she?"

"Ah ha ha ha ha..."

Roger Davis, the boy with dark circles under his eyes among the four, became unhappy when he heard his companions laughing.

He knocked the table with the dinner knife in his hand. "Don't mention it. I don't know why the door knocker went crazy last night. It asked a lot of inexplicable math questions, which locked me out of the door and prevented me from coming in all night."

Having said that, he suddenly became excited.

"Five whole hours! Do you know how I spent these five hours?"

"I lay on the floor in the corridor outside, doing math problems for five hours!"

Noah listened to their conversation word for word and a strange smile appeared on his face.

It is said that people can do anything when pushed into a corner.

But high numbers are an exception.

If you are not good at advanced mathematics, then you are really not good at it.

By the way, the Ravenclaw eagles seemed to have not yet realized what impact the changes in the door knocker would have on them.

So when they came out for class in the morning, no one was left in the common room.

Suddenly I'm looking forward to the evening.

The smile on Noah's lips became even weirder.

……

After breakfast, the Ravenclaw eagles and Slytherin snakes will have their first Herbology class of the semester.

Unlike other classes which are held in the castle, Herbology classes are held in the greenhouse outside Hogwarts Castle.

First-year students are not allowed to leave Hogwarts Castle without permission, so they have to gather at the main entrance of the castle first.

Then, the herbal medicine teacher led them to the greenhouse.

Professor Sprout, who teaches Herbology, is a short and stocky witch with a patched hat on her flowing hair and her clothes are always covered in dirt.

Although her appearance is very simple and inconspicuous, she may be the one with the most normal appearance and personality among the team of ugly teachers at Hogwarts.

As we all know, there are very few normal people in the Hogwarts faculty and staff.

Look at the kind of people Dumbledore recruited.

Old cat girl, black bat spirit, half goblin, half-blood giant, silent ghost, dark oracle, vulture guard, forbidden magic patrol, noseless monster...

At the end, it seemed like something strange got mixed in, but that’s not important.

All we need to know is that Professor Sprout is the only professor in Hogwarts who looks relatively normal.

Standing at the door of the greenhouse, Professor Sprout, who had just finished calling the roll, saw that all the students were present, and he took out a bunch of jingling keys from his pocket.

"This school year's herbal medicine classes will all be held in the First Greenhouse. Before we go in, I have some precautions to tell you."

"There are multiple greenhouses in Hogwarts. The plants inside are very interesting but also dangerous. The lower the ranking of the greenhouse, the more dangerous the plants inside."

"The plants in the First Greenhouse are the least dangerous, but they are not completely harmless. Some of them are poisonous, and some are actively aggressive."

"If you're not careful, you might get hurt or poisoned, and I don't want to see that happen.

"So, you can't let your guard down. You are not allowed to touch any plants without my permission. Do you understand?"

In response to her, a group of young wizards shouted in unison, "Got it!"

Then, Professor Sprout opened the greenhouse door with the key and led the students in.

A smell of damp earth and dragon manure fertilizer hit me in the face, mixed with a hint of fresh grass.

The teaching content of the Herbology class is to teach students to recognize various magical plants and know how to cultivate them, which is equivalent to botany for Muggles.

In Herbalism, students learn how to care for and use plants, and understand their magical properties and applications.

But in fact, this can be simply summed up in one word -

farming.

The content of this course is particularly attractive to international students from China like Noah.

Coupled with Sprout's down-to-earth outfit covered in mud, Noah, a time traveler from China whose ancestors for three generations were all farmers and were tired of poverty, liked her even more.

However, many students are the opposite of Noah.

Because most of the little wizards present have been spoiled since childhood, they may have never done any decent housework since they were young, let alone doing farm work.

Draco Malfoy is one of them.

The first task Professor Sprout assigned them was to learn how to loosen the soil for the plants.

Draco picked up the shovel and dug a few times before he lost his patience and started waving the shovel around randomly, almost hitting Crabbe who was squatting not far from him.

After receiving Professor Sprout's warning, Draco angrily threw the shovel in his hand aside.

"We're here to learn magic! Not to work in the fields like a house elf!"

Noah just glared at him, and Draco shut his mouth awkwardly.

All I can say is that an excellent role model usually makes people unconsciously want to follow and imitate him.

Seeing that such an outstanding person like Noah was digging the soil silently, even though Draco still sneered at the idea of ​​doing farm work in his heart, he still silently picked up his shovel.

What Draco didn't know was that although Noah seemed to be loosening the soil for the plants, he was actually thinking about something else -

What fat earthworms! If I take these to the Black Lake for fishing, I will definitely come back empty-handed, right?

It is said that fishing and sea fishing are the ultimate hobbies for men, and Noah is no exception.

……

The bell for the end of get out of class echoed inside and outside the castle.

The little wizards had been digging in the greenhouse for the whole morning and were all starving.

But the first thing they did after class was not to sprint 100 meters towards the auditorium and cafeteria, but to walk back to their respective common rooms.

They had been digging the soil all morning.

They were all sweaty, emitting an unpleasant sweat odor, and their clothes were covered in dirt.

So they had to go back and take a shower and change into clean and fresh clothes.

Otherwise, with their dirty appearance, they would have been kicked out by Filch, the castle manager, before they even set foot in the hall.

The intricate staircases in the castle were not a big challenge for the clever Ravenclaw eaglets.

Even without the guidance of senior students, the young eagles, who had been groping in the castle for three days, quickly found the right path and arrived at the door of Ravenclaw's common room.

Shirley, who was walking in front of the crowd, raised her hand and knocked gently on the door.

The bronze knocker on the door panel opened its eagle beak and spoke in an extremely gentle voice: "Find the equation of the tangent line of the curve y=lnx at the point (1)."

All the little eagles suddenly fell into silence: ...

What the fuck is this?

雪莉不信邪地又敲了敲，这一次门环换了一个新问题：“求y=x^3-3x^2+4x-5的导数。”

What the hell is this!

Lisa Dupin, Hermione and Shirley's roommate, looked at the bronze door knocker that was talking nonsense and gently kicked the door. "I'm afraid the door knocker is broken."

The door knocker's voice, which originally had little intonation, suddenly carried a hint of dissatisfaction.

"I'm not broken."

It suddenly remembered what Noah had told it last night -

Except for Noah, the other students were exposed to this new knowledge for the first time, so if the questions were thrown to them directly, they would definitely not be able to answer them.

Like the door knocker itself, it couldn't answer Noah's question at first.

So Noah asked Door Knocker to teach the students who came to take on the challenge the prerequisite knowledge needed to answer these questions, so that they could learn on the spot.

Only in this way can their wisdom be tested to the greatest extent.

Doorknocker was deeply impressed by Noah's words.

So, the students gathered at the door of the Ravenclaw common room and began to study advanced mathematics on the spot.

Listening to the door knocker's explanation, within three minutes, all the little wizards at the door had their eyes filled with confusion.

An Indian girl named Padma Patil stood up and said, "I think we should ask the dean to come and deal with it."

The door knocker interrupted the lecture, with a hint of sarcasm in his voice.

"No way, no way, is there really someone who can't even learn such simple knowledge?

"You seek help from adults when you encounter a little difficulty. Are you still the descendants favored by Ms. Ravenclaw? I really don't know how you got into Ravenclaw College."

Padma Patil's face turned purple and she sat back angrily.

Of course, a normal door knocker would definitely not say such words. There is someone else who can say such words——

This is also what Noah taught the door knocker.