This idea is from my friend, credits to her :D

Simon: Hello Clary should we begin studying my lovely parabatai

Clary: Hello Simon yes we should my dumbass parabatai

Simon: Okay i have made a question for you

Clary: bring it on

Simon: ok, let's say Jace stole Magnus's glitter. If Magnus had 8112948921579217682376 bottles of glitter before, and Jace took one bottle, how many would Magnus have?

Clary: *dramatically* oMg oF cOuRsE iTs nOt 8112948921579217682375 bOtTlEs!!! Its 8112948921579217682376, which magnus obviously will acquire back, and in fact probably multiply, an injured Jace with tons of ducks, and there's me, you, izzy, alec and magnus laughing while Jace tries to spawn a spider for Alec

Simon: Absolutely correct you are amazing at math parabatai :D

Clary: yes thank you parabatai my turn-- let's say instead of Jace, Alec took a bottle of Magnus's glitter, what will happen?

Simon: There will be a very cute Malec scene and Magnus saying "Alec take more it's completely alright to take my glitter", an Izzy shouting OTP, a jealous Jace and us monching on popcorn

Clary: Amazing answer good job 

Simon: Wanna go put ducks in Jace's room now?

Clary: great idea >:)