Masozi has in fact spent the first class block NOT in his room, and instead working with Wei Wuxian in the Sinosphere area of the shop. (He got less work done than he’d hoped, and also spent all the mana accumulated over breakfast on finding mals.)

He assumes Lan Xichen is already aware of this, though, and so doesn’t say anything about it when he opens the door. 

“- Oh.” His first thought is that he’s done something wrong again and is in TROUBLE. He tenses up a little. “What is it?”

"I think I come in to check on you and see how you're doing. You maybe get lonely in here? And I am tired of politics and everyone else is on class."

Masozi is blanking on what 'lonely' means even in English, but this is slightly embarrassing so he doesn't say it. 

"- Don't you have to go to a class too?" he says instead. 

"I am junior in Shanghai, I only go to class if I want to. Someone else does my homework for classes I don't want to attend."

- what? That's so confusing. 

"....I thought 'homework' meant - practicing skills that you have to learn to not die...?"

"I am not artificer, math is not useful for me. I have plenty of time to learn calculus when I am graduated."

Masozi was learning calculus just last night! He is kind of upset to discover that this is maybe, apparently, not relevant to his survival! 

"......Should I stop thinking math is interesting, if it's not useful?"

"You are freshman with no idea of your track, you should do all your homework to get sense of what you're suited for. Math is very useful for artificing and alchemy but I am incantations so it is not very useful for me. --Well, you should not do your homework right now, right now learning Mandarin is more important so you can talk with others in enclave."

But math is objectively so incredibly interesting  ....Right. Different people are good at different things.

Masozi feels like there should be a word for that? It would be such a useful word! 

- maybe there IS a word for it and he just doesn't know it yet. And should ask Lan Xichen. 

"Is there a word - in English or Mandarin - for...how some people are more suited to one thing and other people are more suited to other things...?"

"...Talent?"

Masozi repeats the English word. 

"...And how do you say it in Mandarin?" 

He says "talent" in Mandarin.

Masozi repeats it after him, very carefully. 

Okay he - shouldn't say things to Lan Xichen about math because apparently Lan Xichen doesn't want to learn any math or something? 

"....Do you want me to say all the Mandarin things I know?" 

"If you like. Or you can tell me about the math books Wei Wuxian brought you."

This is so confusing!!! 

- Okay. Fine. He - can do his best to tell Lan Xichen about the math books? And ALSO try to do it in Mandarin? 

....It turns out that he is missing so much Mandarin math vocabulary, even when he tries to look it up in his notebook. 

Lan Xichen can help. 

Also, has Masozi realized that he is incredibly cute when he is excited.

Masozi is, in fact, oblivious to this fact! 

...He does sort of want to lean against Lan Xichen's shoulder, if Lan Xichen ends up sitting next to him on his bed and seems willing to let him do this. 

Lan Xichen is very excited about leaning! And also figures that Masozi is probably too oblivious to social dynamics to lean on his shoulder as an elaborate plot to seduce his way into Shanghai enclave. 

He puts his arm around Masozi's shoulder.

Oh, huh, that's - really nice, actually? 

Masozi is confused about why it's this level of nice, but it seems probably not important, so he keeps snuggling up against Lan Xichen and trying to explain grid-based logic puzzles in his incredibly limited Mandarin vocabulary. 

Lan Xichen is not at all confused about why this is this level of nice but instead of doing anything he's going to go home and have his sworn brother mercilessly mock him about it. 

Eventually he says, "I bring you book."

"- A book?" Masozi's entire face lights up. "What sort of book?" 

"My mother reads it to me when I am small." He takes out a copy of the Velveteen Rabbit in Mandarin. "I think it's easier for you to follow because it's for children and has pictures? --It is good use of weight allowance for special thing because I share it with Wangji."

Masozi is not even slightly questioning Lan Xichen's choices around weight allowance! 

He can try to read the book? He's probably going to be very bad at it, though, Mandarin writing turns out to be incredibly hard.

"Do you want me to read it to you?"

"...Okay. Can you say it in Mandarin and also in English each time?"

Masozi snuggles up closer against Lan Xichen so he can listen.