MATHILY and MATHILY-Er guide | RISE Research

TL;DR: MATHILY and MATHILY-Er are selective residential mathematics programs for high school students who want to go beyond standard coursework and engage with proof-based, creative mathematics. MATHILY targets students ready for rigorous independent mathematical work, while MATHILY-Er is designed for students earlier in their mathematical development. Both are highly competitive and run for several weeks each year. If you want a verifiable research output to complement your mathematical profile, RISE Research produces peer-reviewed published papers under 1-on-1 mentorship. Our deadline is closing soon.

Introduction

MATHILY and MATHILY-Er are among the most intellectually demanding mathematics enrichment programs available to high school students in the United States. MATHILY is run by Dr. Jonah Ostroff and Dr. Sarah-Marie Belcastro and is affiliated with Bryn Mawr College. It draws students who are not just strong at computation but who think mathematically at a proof-based level.

The challenge most students face is this: they hear about MATHILY and MATHILY-Er without a clear picture of what the programs involve, how competitive admission is, and what preparation actually looks like. This MATHILY and MATHILY-Er guide covers all of that in one place.

For students who want a research credential to sit alongside their mathematical achievements, RISE Research offers a fully online 1-on-1 mentorship program where high school students publish original research in peer-reviewed journals. A published paper in mathematics, economics, or a related field strengthens a college application in ways a program certificate alone cannot.

What is MATHILY and MATHILY-Er, and who are they for?

MATHILY is a selective residential mathematics enrichment program for high school students who are ready to engage with creative, proof-based mathematics at a university level. MATHILY-Er targets students who are slightly earlier in their mathematical development but show strong potential for rigorous mathematical thinking. Both programs are run by the same team and share the same pedagogical philosophy.

MATHILY is designed for students who have already encountered proof-based mathematics and want to go deeper. MATHILY-Er is the right entry point for students who are mathematically curious and strong but have not yet had significant exposure to formal proof writing.

Both programs are residential and run for approximately five weeks. They are hosted at Bryn Mawr College in Pennsylvania. The curriculum is built around mathematical exploration rather than competition drilling. Students work on problems that have no pre-existing solution in a textbook. The goal is to develop genuine mathematical maturity, not to memorize techniques.

Students who attend MATHILY and MATHILY-Er typically go on to study mathematics, computer science, physics, or related fields at highly selective universities. The programs are well regarded in the mathematics community and among college admissions offices that value intellectual depth over breadth.

You can find official program information at mathily.org.

How do MATHILY and MATHILY-Er work?

Both programs run as residential experiences over approximately five weeks. Students live on campus, attend classes, and spend significant time each day working on mathematics independently and collaboratively. The format is immersive. There are no lectures in the traditional sense. Instead, students discover mathematical results through guided inquiry.

The curriculum covers topics that are not typically taught in high school: combinatorics, graph theory, number theory, topology, and abstract algebra, among others. Instructors introduce a problem or a framework, and students work through the mathematics themselves. Proof writing is central to everything.

MATHILY-Er runs on the same campus during an overlapping period. The two cohorts interact, which means MATHILY-Er students benefit from being around more advanced peers while working at a level appropriate to their current mathematical development.

There are no grades. There is no competition within the program. The environment is collaborative. Students are evaluated on their engagement and mathematical growth rather than on test scores.

The official program page at mathily.org provides the most current information on session dates, location, and curriculum structure.

How competitive are MATHILY and MATHILY-Er?

Both programs are highly selective. MATHILY admits a small cohort each year, typically under 30 students. Acceptance rates are not published officially, but the programs are consistently described as among the most competitive mathematics enrichment opportunities available to high school students in the United States.

A strong MATHILY application demonstrates genuine mathematical curiosity, prior exposure to proof-based mathematics, and the ability to think independently. Students who have worked through books like The Art of Problem Solving series, competed in AMC or AIME, or taken university-level mathematics courses are typical applicants. However, competition results alone are not sufficient. The application includes mathematical problem sets that reveal how a student actually thinks, not just what they have memorized.

MATHILY-Er is more accessible than MATHILY but still selective. It is designed for students who show genuine potential for rigorous mathematics even if they have not yet had formal proof-writing experience.

RISE Research accepts students based on research readiness and genuine intellectual curiosity. Students do not need prior publications or a specific GPA to apply. The program has a 90% publication success rate, meaning the outcome is a real peer-reviewed paper, not a certificate. You can review RISE admissions outcomes to see what scholars have achieved.

How to prepare for MATHILY and MATHILY-Er

The most effective preparation for MATHILY and MATHILY-Er is sustained engagement with proof-based mathematics over several months. Competition preparation alone is not enough. The programs reward students who think carefully and creatively, not students who have memorized the most techniques.

Here is a preparation timeline that reflects what strong applicants typically do:

Three to six months before applying: Build a foundation in proof-based mathematics. Work through How to Prove It by Daniel Velleman or Mathematical Proofs: A Transition to Advanced Mathematics by Chartrand, Polimeni, and Zhang. Engage with combinatorics and number theory at the level of AoPS Volume 1 and Volume 2. Spend time on problems that require you to construct arguments, not just find answers.

One to three months before applying: Practice with the MATHILY application problem sets from previous years if available. Work through AMC 10, AMC 12, and AIME problems not to prepare for competition but to develop problem-solving fluency. Engage with the MIT OpenCourseWare materials on discrete mathematics for additional proof-writing practice.

Final weeks before the application deadline: Focus on the application itself. The mathematical problems in the MATHILY application are the most important part. Write your solutions clearly. Show your reasoning. Do not try to look more advanced than you are. The reviewers are looking for honest mathematical thinking.

For students who want to build a research foundation alongside their mathematical preparation, RISE Research pairs students with PhD mentors in mathematics and related fields. Students produce a peer-reviewed published paper through a 10-week 1-on-1 mentorship program. This kind of research experience builds the analytical depth that makes MATHILY applicants stronger. You can explore RISE student projects to see the range of topics scholars have pursued.

Students who have completed RISE Research arrive at programs like MATHILY with a stronger research foundation than most peers. Our deadline is closing soon. Book a free Research Assessment to find out what is achievable in your timeline.

How do MATHILY and MATHILY-Er help with college admissions?

Attending MATHILY or MATHILY-Er is a strong signal in a college application. Selective universities, particularly those with strong mathematics departments, recognize both programs. Admission to either program demonstrates that a student has been evaluated by expert mathematicians and found to have genuine mathematical ability.

The programs appear in the Common App Activities section. Students should describe the program accurately: residential mathematics enrichment, proof-based curriculum, selective admission. The description should convey what the student actually did and learned, not just that they attended.

The strongest applications pair a selective program like MATHILY with a verifiable research output. A peer-reviewed published paper in mathematics or a related field adds external validation that a program certificate alone cannot provide. RISE scholars have achieved an 18% acceptance rate to Stanford, compared to 8.7% for the general applicant pool. At UPenn, RISE scholars are accepted at 32%, compared to 3.8% for general applicants. These outcomes reflect what published research adds to an already strong academic profile. You can review the full RISE results for more detail.

Frequently asked questions about MATHILY and MATHILY-Er

How do I register for MATHILY or MATHILY-Er?

Applications open each year through the official MATHILY website at mathily.org. The application includes a mathematical problem set, short essays, and a teacher recommendation. Students should check the official site for the current application cycle and requirements, as details are updated annually.

Is MATHILY worth doing for college admissions?

Yes. MATHILY and MATHILY-Er are recognized by selective university admissions offices as credible signals of mathematical ability. Admission alone demonstrates that a student has been evaluated and selected by expert mathematicians. The programs are listed in the Common App Activities section and carry genuine weight for students applying to mathematics and science programs at top universities.

How hard is it to do well in MATHILY?

MATHILY is designed to be challenging even for mathematically advanced students. The curriculum covers topics most students have never encountered, and the proof-based format requires a different kind of thinking than competition mathematics. Students who arrive having worked through proof-writing resources and who are comfortable with mathematical uncertainty will adjust more quickly. The environment is collaborative rather than competitive, which reduces pressure while maintaining intellectual rigor.

What resources should I use to prepare for MATHILY?

The most useful resources are proof-based mathematics textbooks, AoPS problem sets, and prior MATHILY application problems if available. How to Prove It by Velleman is widely recommended. AMC and AIME problems build problem-solving fluency. MIT OpenCourseWare discrete mathematics materials provide additional proof-writing practice. The goal is mathematical maturity, not competition ranking.

How does research experience help with MATHILY preparation and applications?

Research experience builds the analytical depth and independent thinking that MATHILY rewards. RISE Research is the strongest option for students who want a verifiable research credential alongside their mathematical preparation. Through 1-on-1 mentorship with PhD-level experts, RISE students produce peer-reviewed published papers with a 90% publication success rate. You can explore RISE publications to see what scholars have produced. Published research in mathematics or a quantitative field strengthens both the MATHILY application and the broader college application in ways that program attendance alone cannot replicate.

Conclusion

MATHILY and MATHILY-Er are two of the most rigorous mathematics enrichment programs available to high school students. They reward genuine mathematical thinking, not just competition performance, and they are recognized by selective universities as credible evidence of mathematical ability.

Preparation takes time. Students who engage seriously with proof-based mathematics over several months, work through strong resources, and approach the application problem sets with honesty and care give themselves the best chance of admission.

For students who want a published research paper to complement their mathematical profile, RISE Research provides 1-on-1 mentorship with PhD-level experts and a 90% publication success rate. A peer-reviewed paper in mathematics or a related field is a verifiable, externally validated credential that appears directly in the Common App. You can learn more about RISE mentors and the depth of expertise available to scholars.

Our deadline is closing soon. If you are a student targeting programs like MATHILY and want a real research outcome on your application, schedule a free Research Assessment and we will tell you exactly what is achievable in your timeline.