"It's, um. About gravity? Bigger things have more of it, and if something smaller is close enough it gets... caught... I'm not explaining this right, am I." 

(It does not seem to have occurred to Kinsei to wonder why Masozi is in a Mandarin-language math class with him.) 

Math is supposed to have One True Answer! The lesson says she should lie?? Why does math involve lying!

Also this math class is in Mandarin why does everyone keep talking in English. Mei doesn't understand anything and she is going to die and Ayako will have to make it to graduation alone because Mei is too stupid to understand how to lie to math.

Well, Masozi is going to slightly increase the total amount of Mandarin being spoken by asking Wei Wuxian to read the instructions to him out loud in Mandarin so that he can copy out phonetically in English letters the sound that goes with each character. 

Is this time for a lesson in the International Phonetic Alphabet? Wei Wuxian thinks it is absolutely time for a lesson in the International Phonetic Alphabet.

Amazing! 

Why is this class in English. Lan Wangji thought it was in Mandarin. He understands absolutely nothing that is happening here. Math is supposed to have rules. Math is one of his favorite academic subjects because there is always a right answer and a wrong answer.

He is going to sit over here next to Mei who also doesn't speak non-spellcasting English.

Kinsei looks over at the other people who seem like they're having a bad time and haven't been speaking exclusively English.

He is not quite brave enough to actually get up and introduce himself to two people with power-sharers, though. 

Mei had not quite realized before that "some kids take classes in languages they don't know so they can also get language credit for it" would mean that her math class might be someone else's Mandarin class, or how distracting that would be.

She looks at Lan Wangji as he sits down by her. Well, upside, he won't be talking a language she barely understands. Downside, she does not think he is going to produce more explanation of their assignments than "mn".

Maybe that Japanese kid over there has some idea what they're doing. "Hey, I'm Mei Masane. Are you good at math?"

"I'm Kinsei Saito. I'm. Good at math usually?" 

And now that someone else has made the first move it's probably fine to move so he's next to Mei now? 

The rules say that he is supposed to do his homework and follow class instructions. The class instructions say he's not supposed to follow the rules of math. He is very quietly having a meltdown.

Mei suggests to the person currently sitting next to her that perhaps they could trade seats with Saito-han and thanks them as they vacate their chair.

Right okay thank you. The fact that that is a thing people can just do is kinda terrifying but it's fine probably? 

"Thank you. Uh. I can try to explain the assignment I think? But I'm good at... trigonometry, and things, this isn't really..." 

"--oh, so you had a question about the earth orbiting the sun-- so you know how when you drop an apple it falls to the ground? That's because big things tend to pull small things towards themselves. We call that 'gravity.' And the sun is much bigger than the earth so it keeps pulling the earth towards it."

“….Then why doesn’t the earth just fall into the sun?”

"Great question! Because the earth was going very fast this way"-- he draws a line-- "and then the sun was here" --dot-- "and so they averaged out into a curve like this"-- he draws an ellipse-- "that's also how spaceship orbits work."

"Did you know that people went to the moon?"

Masozi goes very still. "- What? How?" 

"Okay, so, when you shoot something out of the back of something, it pushes it forward. That's called thrust. And if you build a machine that makes a really big explosion for long enough it can push the machine high enough that you can reach the moon. --I really need a visual aid for this, maybe I can whip something up in shop."

Masozi's eyes go out of focus for a few seconds as he tries to - process all of that, fit it into anything he understands -

- oh right he's not safe he has to watch for mals and he has to remember that no one else is careful enough and his survival here depends on himself alone– 

He takes a deep breath. "I - that'd be really interesting but I think I should try to learn what's in this class first and not get distracted?" 

"Oh, right," he says, as if this just occurred to him. "So, uh, barrels of oil in China-- a barrel is like a meter tall, right--"

Lan Wangji is having a very small emotional crisis. 

First of all, the math is telling him to break the rules of math and he doesn't understand how to do this. You're not supposed to just guess on math problems. There's a right answer.

Second, Wei Wuxian keeps smiling, which is normally good, except now he's smiling at Masozi and being interested in Masozi and Lan Wangji has never gotten him to smile that much. They're saying something in English and Lan Wangji doesn't speak English and they could be saying anything. Maybe Wei Wuxian is confessing his love to him. Maybe they're going to get married and Lan Wangji has accustomed himself to a life of celibate devotion but it is one thing to be accustomed to a life of celibate devotion and another to live it while your love is getting married to someone else and smiling at him. Lan Wangji wants those smiles to be reserved for himself alone.

Maybe he could stab Masozi with Bichen.  

"So, uh," Kinsei tries again, "I-- I think it's asking us to try and answer the questions without really doing... math about it?"

Masozi is still raptly listening to Wei Ying's explanation of how to answer the barrels-of-oil question. 

"How can you answer a math question without doing math?"

"I think they're not really math questions? Like-- it wants to know the size of the earth and how much bigger the sun is, but it hasn't told us the numbers we'd need to actually do math to get a real answer, and instead we got an instruction sheet that says to just go ahead and make a guess that feels right?"