This post is advice for problem-solving beginners in math. It’s halfway between Getting to know problems and Imperative statements in geometry don’t matter, but now I got it down to three words that are easy to remember: don’t be GPT-3.

What does that mean?

Basically, I see a failure case in a lot of beginners who get fixated on some (often superficial) detail or wording in the problem statement, and then try to pattern-match it to something they read somewhere before. In doing so, they stop actually thinking, and that’s a disaster recipe.

The reason I call this “don’t be GPT-3” is in reference to this toy problem:

Prove that if $\theta$ is a real number for which $\cos \theta$ is an integer, then $\sin \theta$ is an integer.

For a good high school math …

The 2026 American Masters in Math took place from May 22 to 25, 2026.

On the whole it went better than I expected. Because from the insider view, working with OMEGA reminded me a bit of… okay, let me make up an analogy. You know how AlphaGo often wins its games by just a few points, but always wins?

This AMM reminded me of that. Things often happened at the last possible moment, yet still technically in time.Scores when? So things seemed haphazard on the inside, and I was quite stressed most of May. But somehow in the end it all worked.

It’s also hard for me to overstate how much of AMM 2026 rested on Yia’s shoulders. Up until April or so, it felt that Yia was singlehandedly doing everything except the exam problems. (She did eventually get help: I thank Hong Liu, Kathy Lin, Walter …

Cubics

Last summer I taught a lecture at MOP about curves of degree higher than 2. I finally posted the handout from that lecture on my website, because a lot of students have been asking me repeatedly, and one of my students went so far as to start a petition.

I am of course flattered and grateful for the enthusiasm. But there was a reason I didn’t post it.

Theater

That reason comes down to the following quote from my 2023 post:

You’ll notice that I’ve started using words like “delivery” or “performance”, and that’s deliberate. To do lectures well, you need to rehearse things like not saying “um”, choosing really flashy or shiny topics, managing blackboard space, keeping an audience engaged, and cutting out content to streamline the presentation (whereas in writing, you can e.g. put digressions …

For high school math olympiad students, OTIS XII applications are out, due August 1, 2026.

But I’m really going to use that short announcement as an excuse to describe the second most common error I see on the OTIS application (the most common error is this type-error I wrote about in 2023). The mistake is so obvious I feel stupid writing about it, but I keep seeing it. So I’m going to record it anywayFree blog advertisement every time I see this mistake again, right?, even though most of the readers of the blog will laugh at me.

Here’s a problem I made up to demonstrate it:

Problem: For real numbers $a$ and $b$, determine the minimum possible value of $$f(a,b) = (ab-1)^2 + (a-3)^2 + (b-3)^2 …$$

TL;DR: New Pelican blog! You can email-subscribe via https://list.evanchen.cc.

If you’re reading this, that means I’ve successfully moved my blog from WordPress to Pelican! If you want to see how this website was made, you can see the entire source repository. There might be some things off with the migrated old posts; open a pull request if you spot any and I’ll be grateful.

See the subscribe page if you want to subscribe.

1. New features for readers

Really the primary motivation for the migration is easier maintenance for me. But readers might notice a few nice things:

• A new skin that’s more minimalist.
• Sidenotes.
• Server-side LaTeX rendering instead of the hacky WordPress images.
• Cleaner URL scheme: this post will be blog.evanchen.cc/pelican instead of the old URL scheme with the dates. (The old URL’s will still be redirected …

Life isn’t a straight line. Finding your dream career involves a lot of twists and turns, like a river. In my search for the perfect job, I find myself constantly changing course, because even though planning is helpful, the plans themselves are useless.

In past years, I’ve been through sailing, college consulting, and fashion design. And now I find myself eating my words from last year. Despite how much I hate New York, I’m thrilled to announce the upcoming opening of T.O.A. Asian FusionPlease forgive the slight RAS syndrome in the name. at 33 Sunrise Hwy, Merrick, NY 11566.

Here’s the press release from Newsday on the Merrick location:

T.O.A. Asian Fusion is on a roll. Four months after opening its fifth location, in East Islip, the restaurant group has announced its sixth: Evan …

Some of you have probably noticed that I’m helping with organizing a new contest and are asking what exactly this is. So far, I haven’t said much about it because so much is up-in-the-air (and that’s still true).

However, with the first few acceptances and registrations coming out, I’m going to post an FAQ and few quick thoughts of my own. Just to be clear, everything here is my own personal commentary and views and not those of my employer or OMEGA generally.

What is OMEGA?

OMEGA (Organization for Math Engagement and Growth in America) is a new 501(c)(3) whose ambitious long-term goal is to build great, robust math programs for thousands of students all across the USA (whether competition-like or not).

However, that is a pipe dream, because OMEGA is also about four months old and has a whopping four staff, many of …

Here’s a section from the H-group Hanabi strategy page:

LINES

During your turn, part of figuring out the best move involves looking into the future to see what the next player will do. If they discard, will it be okay? Is there some obvious clue that they will do? And so on.

As you get better at Hanabi, you will need to do this prediction not just for the next player, but for an entire go-around of the table. And as you really get good at Hanabi, you will need to do this for as far in the future as you can reasonably predict. (Sometimes, this means 15 moves or more in the future.)

Similar to chess, initiating a move in which you can predict the next sequence of moves is called initiating a “line”.

In post-game reviews, we will often compare and hypothetically “play through” two different lines …

Announcement for the USEMO 2025:

• The USEMO 2025 will be held on October 25 - 26, from 12:30pm - 5:00pm ET each day.
• For competitors, registration will open in early October on AoPS.
• If you’d like to volunteer for grading, the signup for that is posted on the website now too. You should sign up no later than October 25 for that.

As usual, all relevant info at https://web.evanchen.cc/usemo.html.

I had a student at MOP ask me something equivalent to “how should I study while at MOP?”There is also a question about whether you should be studying much at MOP at all — you could also spend a lot of time making new friends, for example. That’s a value judgment that I think is better left to individuals and I won’t comment on it further in this post. For those of you that don’t know, MOP is the three-week summer camp for the USA’s team to the IMO.

At first I was going to just link my FAQ. But then I thought about it a bit more, and I was surprised to find that my answer was not the same as the general how-to-study FAQ. The additional condition “while at MOP” was enough to cause me to stay up that night writing an entirely different …