Chapel Hill Math Circle will resume in person on Sept 10, 2022!
The Chapel Hill Math Circle brings students together to explore new ideas and work on challenging problems with like-minded students. We meet about 2 Saturdays per month during the school year.
Please check our calendar for date, topics, and handouts.
Circle | Level | Time | Location |
Moebius Noodles | Recommended for kindergarteners and first graders and their families: one or more parent(s) or other adult(s) is expected to attend with their child | Saturdays 10:30 – 11:30 am |
Phillips Hall room 206 |
Beginners Group | Recommended for grades 1 – 3. | Saturdays 9:00 – 10:00 am |
Phillips Hall room 206 |
Elementary Group | Recommended for grades 3 – 5 . | Saturdays 9:00 – 10:00 am |
Phillips Hall room 208 |
Intermediate Group | Recommended for middle school students (grades 6 – 8). |
Saturdays 10:30 – 12:00 noon |
Phillips Hall room 208 |
Advanced Group | Recommended for high school students (grades 9 – 12) who are comfortable using Algebra. |
Saturdays 10:30 – 12:00 noon |
Phillips Hall room 220 or 224 |
Below are a few puzzles to whet your appetite:
What is the maximum number of pieces you can divide a watermelon into with four straight cuts, if you are NOT allowed to rearrange the pieces between cuts? With five cuts?

There are 100 light switches on the wall, all turned off. A hundred toddlers come by. The first toddler flips every switch. Then the second toddler flips just switches 2, 4, 6, 8, … etc. Then the third toddler flips switches 3, 6, 9, 12, … etc. This pattern continues until finally the 100th toddler flips just switch number 100. How may lights are turned on at the end?
A military base has a number of identical hoverplanes. Each hoverplane can carry enough fuel to fly exactly halfway around the planet. Hoverplanes do not use any fuel while hovering stationary in the air, and hoverplanes can transfer any amount of fuel between each other while in the air. What is the minimum number of planes that are needed so that one plane is able to get all the way around the planet and all assisting planes return safely to base?