Fawn Nguyen

21st century mathematics – 2025 An online learning experience for math teachers Registration for the 2025 program has closed. If you would like to be notified about future editions of the program, just fill out this form. If you …

closed out today with a presentation from @fawnnguyen.substack.com!

s/o to @jlanier.bsky.social for running this program for 3 consecutive years; you can learn more about the 2025 schedule here:
justinlanier.org/21st-century...

+ hopefully can join for some/all in 2026! (far off as next summer is)

[New Post] Ontario Math Links - My favourite #math related links from this week:

ontariomath.blogspot.com/2025/08/math...

Links and help from @astadel.bsky.social @howiehua.bsky.social @fawnnguyen.substack.com @karencampe.bsky.social @percybuttons3.bsky.social & more #MathChat #MTBoS #iTeachMath

My 7th Graders Are Better Than Yours You’d brag too if they were yours.

NEW Post: My 7th Graders Are Better Than Yours :) fawnnguyen.substack.com/p/my-7th-gra...

Hudson Hawk What is your favorite math problem?

A slightly different questions is 'What is your favourite math(s) problem?'

I really enjoyed reading some of the answers shared by @fawnnguyen.substack.com in this post:
fawnnguyen.substack.com/p/hudson-hawk

Doing Right by the 8 Mathematical Practices Because doing wrong by them is just wrong

NEW Post: Doing Right by the 8 Mathematical Practices fawnnguyen.substack.com/p/doing-righ...

Wow. Thank you so much, Jennifer. My God, I saw a commercial for back-to-school sales yesterday. Don't forget to just do nothing, Jennifer!

I know you picked the very best four.
(Am I ever going to see you again? Your kids will turn pro on the ice any time soon.)

I read godly written initially.
🙏

Except for a perfect baguette, hence "perfect." I don't want it any other way. :)

Permission to Go Off Script Building Thinking Classrooms practices are powerful—but they’re not all-or-nothing

New post: Permission to Go Off Script
Building Thinking Classrooms practices are powerful—but they’re not all-or-nothing
fawnnguyen.substack.com/p/permission...

First Desmos Geometry Lesson Where squares fall apart—and that's the point

NEW Post: First Desmos Geometry Lesson fawnnguyen.substack.com/p/first-desm...

JRMF Community Math Circle

JRMF Community Math Circle jrmf.org/events/jrmf-...

This is an excellent piece, but... Fawn's Wolves and Sheep puzzle (linked to in the first sentence) is vexing me. I'm very vexed.

This makes me very happy, Matt!

Hudson Hawk What is your favorite math problem?

NEW post: Hudson Hawk (What is your favorite math problem?) fawnnguyen.substack.com/p/hudson-hawk

Thank you for filling out the survey and I shared the responses.

The Illusion of Thinking Reasoning models collapse—kids don’t have to

NEW post: The Illusion of Thinking
fawnnguyen.substack.com/p/the-illusi...

Yay!! Now, I'm curious which one was yours. I'm so excited to see all the different responses, a bunch I'm not sure I know!

Haha!! But I do have just one answer for all those "what's your favorite ___?" But math, impossible.

Please don't overthink it—just answer like you would if I asked your favorite movie, musical, or ice cream flavor. Either something pops into your head, or it doesn’t!

Hi Everyone, I hope you can help me answer an anonymous, SHORT 2-question survey: forms.gle/Ri58V4oSEyeR...
Thank you in advance! 🙏❤️

Hi Andrew. Be nice.

The Breakfast Club With syrup stains and borrowed answers

NEW post: The Breakfast Club fawnnguyen.substack.com/p/the-breakf...

I miss you so much, John. Wish our paths would cross again.

Rude

Cracking the Strategy A fourth-grade window seat to line plots and dot paper fractions

NEW post: Cracking the Strategy, when a 4th grader explains her thinking
fawnnguyen.substack.com/p/cracking-t...

New lesson added to our free lesson library!

__The Tax Collector__

This is an expanded writeup of my original @nytimes.com Numberplay writeup from 2015. Features a tie-in to my more recent @ted-ed.bsky.social riddle too!

Great for grades 4 - 10.

mathforlove.com/lesson/tax-c...

May I just add this thread to the post?

You're just showing off, Benjamin. Brilliant!

Mainly because things are already set—for now. With tight deadlines & limited resources, it’s tough to add new things. Also, I want these tasks included a certain way: no answer key is one. I want Ts to engage with the problems the same way they ask their students to.

I put a lot of these kinds of problems (though not this particular one, obviously, since it was new to me) in our supplemental curriculum. I don't know if supplemental curricula are always the way to go, but there are advantages to having something you can add in anywhere.
mathforlove.com/curriculum