About the Course

Number Theory

  • Grades 7-11
  • Advanced CTY-Level
  • Residential
  • Mathematics

Called "The Queen of Mathematics" by the great mathematician Carl Friedrich Gauss, number theory is the study of the natural number system from which all others are derived. Despite the simplicity of the natural numbers, many accessible problems in number theory remain unsolved. For example, the Goldbach Conjecture, formulated in 1742, which posits that every even integer larger than 2 is the sum of two prime numbers, has defied all proof attempts. In this proof-based course, you’ll learn the major ideas of elementary number theory and the historical framework in which they were developed. While strengthening your ability to analyze and construct formal proofs, you and your classmates will explore topics such as the Euclidean Algorithm and continued fractions, Diophantine equations, Fibonacci numbers and the golden ratio, modular arithmetic, Fermat’s Little Theorem, and RSA public key cryptography. You’ll leave the course with an appreciation for the elegance of theoretical mathematics and the ability to craft rigorous arguments.

Typical Class Size: 16-18

Course Overview

Summer Dates & Locations

Registration deadline:

After May 31, 2024, registration is available upon request pending eligibility and seat availability. To request placement, email [email protected] after submitting a program application.

Session One

Dickinson College
Carlisle, Pennsylvania
Residential cost: $6,599
Commuter cost: $5,799
Session in Progress

Session Two

Dickinson College
Carlisle, Pennsylvania
Residential cost: $6,599
Commuter cost: $5,799

Testing and Prerequisites

  Math Verbal
Required Level Advanced CTY-Level Not required
Check your eligibility using existing test scores If you do not have existing test scores:

Students must achieve qualifying scores on an advanced assessment to be eligible for CTY programs. If you don’t have qualifying scores, you have several different testing options. We’ll help you find the right option for your situation.

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Course Prerequisites

Number Theory requires:

1 prerequisite

Geometry and Algebra 2

Cost and Financial Aid

  • Tuition
    • Varies
  • Application fee
    • Nonrefundable Application Fee - $50 (Waived for financial aid applicants)
    • Nonrefundable International Fee - $250 (outside US only)

Financial Aid

We have concluded our financial aid application review process for 2024 On-Campus Programs. We encourage those who may need assistance in the future to apply for aid as early as possible.

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Course Materials

Students should bring basic school supplies like pens, notebooks, and folders to their summer program. You will be notified of any additional items needed before the course begins. All other materials will be provided by CTY.

Sample Reading

These titles have been featured in past sessions of the course, and may be included this summer. CTY provides students with all texts; no purchase is required.

  • Number Theory: A Lively Introduction with Proofs, Applications, and Stories, James Pommersheim, Tim Marks, and Erica Flapan

About Mathematics at CTY

Explore the study of shapes

Many of our courses allow students to describe the world around them in basic and profound ways. Our younger students learn about shape, scale, and proportion in Geometry and Spatial Sense. Middle School students explore beautiful real-world applications of lines; analyze data based on curves that fit a uniform, symmetric and bell-shaped, or skewed pattern in Data and Chance. And advanced students explore the underlying mathematics and fundamental characteristics of shapes, distance, and continuous deformations in our proof-based Topology course.

Dive deep into logic and reasoning

Our courses in formal logic give you the tools to question the world around you. Inductive and Deductive Reasoning introduces younger students to different types of reasoning, as well as the strengths and weaknesses inherent in various forms of critical analysis. Older students explore how logical reasoning can explain (or fail to explain) counter-intuitive results in Paradoxes and Infinities, or take a more rigorous approach to formal logic in Mathematical Logic.

Meet our instructors and staff