There is a job posting for a mathematics staff writer at @quantamagazine.bsky.social: simonsfoundation.wd1.myworkdayjobs.com/en-US/simons... Maybe this is good for you or somebody you know! #MathSky 🧮 #iTeachMath ♾️

since there are only 7 Clay Millennium Prize Problems (one of which has already been solved) ... this must be paradigm-shifting work, excited to see AI naysayers proved wrong!!

people talk about Christmas on 1225 and about the current year being a perfect square but who is going to tell you that 1225 is a perfect square??? ... i am. and i leave it to the reader to find the square root (not a trick!) 🎁² = 🎄 🎁 = ?

people talk about Christmas on 1225 and about the current year being a perfect square but who is going to tell you that 1225 is a perfect square??? ... i am. and i leave it to the reader to find the square root (not a trick!) 🎁² = 🎄 🎁 = ?

since there are only 7 Clay Millennium Prize Problems (one of which has already been solved) ... this must be paradigm-shifting work, excited to see AI naysayers proved wrong!!

a lot of people are aware that you can factor 2025 = 45² i'm honored to announce the factorization 2026 = (45-i)(45+i)

have you seen this result? www.desmos.com/calculator/8... if not... can you prove it? #iTeachTrig 📐 RESULT for A, B, C that sum to 180° (e.g. interior angles of a triangle): sin²(A) = sin²(B) + sin²(C) - 2cos(A)sin(B)sin(C) #MathSky 🧮 #iTeachMath ♾️

MathUnderflow: "Do mathematicians have an ethical role to play, regarding the AI bubble?" mathoverflow.net/questions/50...

seconded... ❗

Interesting call

how do I translate a polar coordinate graph in Desmos? like if I graph r = cos(4 theta) is there a way to move it around in Desmos? say, 3 to the right and 4 up?

ayyy a second edition! if i could read, this would be a necessary acquisition cc #iTeachMath ♾️ #MathSky 🧮

Good read! Note that the full position paper is linked *at* the link, and is quite specific with its analysis of some "SoM" claims. Here is a direct link to save a click: www.mathedleadership.org/wp-content/u... #iTeachMath ♾️

in the other direction, are there capital numbers, like capital letters. also a good [gosh darn] question scholar.google.com/scholar?clus... Brizuela, Barbara. "Inventions and conventions: A story about capital numbers." For the learning of Mathematics 17.1 (1997): 2-6.

Find an 8 digit calculator word (rotate 180° and read the digits as letters) whose middle four digits (without rotation) are consecutive integers. I believe there is a unique solution and/but would be happy to be proved wrong! #iTeachMath ♾️ #MathSky 🧮

2️⃣2️⃣ for 2️⃣sday A reminder that I cocreated "the 🐐 word game" (many people are saying this!) and it is 🆓 to download 🆓 to play and 🆓 of ads — 🎻🧱 #FiddleBrix Tuesday, December 2, 2025 0:22 (no hints!) 🟪🟪🟪🟨 🟪🟨🟨🟨 🟪🟦🟦🟨 🟦🟦🟦🟨 fiddlebrix.com

Remarkably* clear exposition! *literally, since I'm remarking on it cc #iTeachMath ♾️

some of y'all will claim 2 pi = 1 tau 🤨 but i'm out here looking at 2 tau like ττ

math classes emphasize sum and difference formulae for sine i.e. sin(x+y), sin(x-y) yet rarely broach the multiple angle formulae for products e.g. sin(xy). not sure if this is just a sign of the times.

lotta math classes teach about completing the square without ever asking why the square felt incomplete in the first place 😔

Armchair Education Experts (AEE): US 🇺🇲 students have fallen behind in mathematics & need to be better prepared for the as-yet-unknown jobs/needs of the future 🔮🧮🔢✨ me: so we should teach math differently now AEE: no me: AEE:

"A mathematician is a machine for turning coffee into [gatekeeping, opportunity hoarding, anxiety & trauma, scarcity mindsets, ...]"

non-Euclidean geometry proofs where the two columns eventually meet 💡

P adic! At The Disco

εεεεδεεεεδεεεεδεεεεδ... Every four ε, there is a δ.

[fed up] fine, on the count of 3, i will explain how limits work: 1 2 2 and ½ 2 and ¾ ...

every open bar with a cover has a finite subcover

petitioning to replace "there is a lid for every pot" with "there is a delta for every epsilon"

lol at the answer being "Yes" click thru to see more! #iTeachMath ♾️ #MathSky 🧮

A now well-known-ish open conjecture! One reason that the tetrahedron problem is tougher is that the triangle inequality on each side is necessary but NOT sufficient. To see a deeper reason for the difficulty, the condition on a tetrahedron involves the en.wikipedia.org/wiki/Cayley%... #iTeachMath

[me after being inexplicably granted access to the hyperuranion] me: wow, so this is the so-called "Platonic realm"! perfect circle: perfect square: me: lmao do y'all ever call it the "Friend Zone"???

yesterday students showed me math from something called "TickTock" (i think it's like SnapGram). it involved moving whiteboard markers to change their arrangements from 4321 to 1234; here it is in typed form: with one X and O switch, convert: X X X X O X X X O X X O X to its reverse! #iTeachMath ♾️

Article ❌🔓: archive.ph/coei4 If you can access The Atlantic, the piece can be found here: www.theatlantic.com/ideas/2025/1... ‘A Recipe for Idiocracy’ What happens when even college students can’t do math anymore? By Rose Horowitch

#TryMathsLive s/o @davidkbutler.bsky.social!

no calc before uni but advisor put me on REU about p-adic dynamics; thought math PhD could be cool! took Chinese as a sidequest but didn't study abroad; dormmate brought me to an info session on fellowships. got a Fulbright to learn about Chinese math T training; back in US, got a PhD in Math Edu.

> Bernshteyn took a logic course with Anush Tserunyan... “She should take all the credit for me being in this field,” he said. “She really made it seem that logic and set theory is this glue that connects all different parts of math.” #MathSky 🧮 www.quantamagazine.org/a-new-bridge...

33 more years until 11 23 58 time to start brainstorming 🧠⛈️ fun ways to celebrate

consider a subset of the first N positive integers: S ⊆ {1, ..., N} call S "mid" if, for every integer n, if n-1 and n+1 are elements of S, then n is in S. #MathSky 🧮 #iTeachMath ♾️ example: if N=5, the set {2,3,4,5} is a mid subset. ⭐️ find a formula f(N) for the # of mid subsets of {1, ..., N} ⭐️

an academicky update: i finally got a preprint ("UNCORRECTED PROOF") for a chapter i wrote! www.researchgate.net/publication/... this is Chapter 5 (Curriculum. Creativity in the Mathematics Classroom) from: Creative Contexts: Our Worlds as Actors in the Dynamics of Change (ISBN: 978-3-032-12282-7)

me: we can write 5·4·3·2·1 as 5!, so, if it helps, we could use a modified exclamation mark with a + rather than a · below the vertical part to represent for e.g. 5 the expression 5+4+3+2+1 students:

*students feel blah about quadratics* me:

in base 10, sometimes two numbers with only 0s and 1s have a product of only 0s and 1s. e.g. 11010*100001 = 1101011010 ➡️ under what conditions does this occur? cc #MathSky 🧮 bcc #iTeachMath ♾️

Prealgebra Algebra 1 Algebra 2 Linear Algebra Abstract Algebra Algebraic Geometry Algebraic Number Theory Algebraic Topology Algebra Algebraic Etymology Algebraic Ontology Algebraic Entomology Algebraic Oenology Algebraic Otology Algebraic Philology Algebraic Astrology Postalgebra

[finally integrating algebra & geometry] me: now remember, when you have a function that sends x to ax²+bx+c, what role do the coefficients play? students: a² + b² = c²? me: students:

🌟Reminder🌟 Cannot say f(x)=x² is not injective aka one-to-one without explicitly stating its domain. For example, the aforementioned function is one-to-one on the domain {-11,11}.

students: wait is "PT" short for Pythagorean Theorem or Pascal's Triangle? me: yeah

"It is the first time a mathematician has received NSW’s highest honour for scientific endeavour." cc #iTeachMath × #MathSky!

this is my feeling about modulo (among gen pop)

A few 👀 @catrionaagg.bsky.social geometry puzzles that definitely won't totally consume your Sunday or November or ...

every so often i recall that, 15 years ago in Fall 2010, i started a little storybook style introduction to Galois Theory: imgur.com/a/galois-the... i sent it out to the class & prof to ask if anyone was interested in my continuing; no one was. alas, i moved on thereafter. well. it still reads ok!