Every year for a quarter century, chemistry teacher Anthony Simonelli made the same offer to his students at Baldwin High School: score a perfect 100 on the New York State Chemistry Regents and he would hand you a $100 bill himself. For 25 years, nobody collected. A few students came painfully close over the years, and every June the bill stayed in his wallet. Then Jojo Yawson's exam came back.

The last exam in the pile

Yawson took the Chemistry Regents in June, at the end of a full year of Simonelli's class. When the scores were graded, his was the last one to come back, and it came back perfect. Simonelli has described the moment as the one he had been promising his students for 25 years and had privately started to wonder if he would ever see: a flat 100, with the last student graded, in what may be one of the final years of the exam as Baldwin students know it.

A perfect score on the Chemistry Regents is a different thing from a great one. The exam stretches across everything a student learns in a year, from atomic structure and bonding through stoichiometry, kinetics and electrochemistry, in a long run of multiple choice questions followed by constructed responses where a single misplaced unit or rounding slip costs a point. Scores in the 90s show up every June in strong classrooms across Long Island. A 100 means not one point dropped anywhere, on any page, and in 25 years of Simonelli's classes it had never happened.

A bet designed to be lost

Simonelli started the challenge as a motivator, the kind of standing offer a teacher makes knowing the odds are on his side. One hundred dollars for a perfect paper, delivered personally. The point was never really the money. It was to put a target on the wall that made students chase the last few points instead of settling for a safe 85, and for two and a half decades it worked exactly that way: plenty of chasing, no payout.

When Yawson broke the streak, Simonelli paid up as promised. Yawson's mother has suggested the bill belongs in a frame rather than a register, which seems right for a piece of paper that took 25 years to change hands.

The student who did it

Yawson's path to the perfect paper was not the one you might sketch for a test-day phenom. He was homeschooled for several years and has navigated learning differences on his way through school. At Baldwin High School he writes for The Golden Wave, the school's student news site, and he has told interviewers he plans to study civil engineering, a field that will ask him to be exactly as allergic to small errors as the Regents did.

That arc is part of why the story has traveled beyond Baldwin. A standing bet that survives 25 years of honors students and falls to a kid who spent years learning outside a traditional classroom is the kind of result that says more about persistence than about test prep.

The price of perfection just went up

The timing adds one more wrinkle. Simonelli has said the Chemistry Regents is changing next year, as New York State continues replacing its long-running science exams with new versions built on updated learning standards. Whatever the new exam looks like, the version that stood unbeaten through 25 years of Baldwin chemistry students now has exactly one perfect conqueror on record in Simonelli's classroom.

The challenge itself is not retiring. Simonelli is raising the stakes to $200 for the next student who runs the table, which means somewhere in Baldwin there is a sophomore who just got twice the reason to double-check their significant figures.

For everyone else, the takeaway is simpler. Somewhere between the periodic table and the June exam schedule, a Baldwin teacher spent 25 years telling students that perfect was possible, and he finally got to pay for being right.