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Chapel Hill Math Circle will begin again online in Spring 2021, starting Jan 23, 2021. Some groups may also occasionally meet outdoors for socially distanced activities.

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.

Note: in order to keep costs low and bureaucracy to a minimum, for Spring 2021, Chapel Hill Math Circle will be run privately and will not be affiliated with UNC-Chapel Hill in any way.

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
Zoom meeting number will be posted here
Beginners Group Recommended for grades 1 – 3. Saturdays
9:00 – 10:00 am
Zoom meeting number will be posted here
Elementary Group Recommended for grades 3 – 5 . Saturdays
9:00 – 10:00 am
Zoom meeting number will be posted here
Intermediate Group Recommended for
middle school students (grades 6 – 8).
Saturdays
10:30 – 12:00 noon
Zoom meeting number will be posted here
Advanced Group Recommended for
high school students (grades 9 – 12) who are comfortable using Algebra.
Saturdays
10:30 – 12:00 noon
Zoom meeting number will be posted here


Below are a few puzzles to whet your appetite:

watermelon2

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?


lightSwitches2

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?


hoverplanes

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?