Pedaling a Bicycle

Bicycles are everywhere. Most of us know how to ride them. Many ride a few times a week. But have you thought about how the gears of a bike work? It’s stranger than you might think.

A little bicycle history…

I started the meeting with a notice/wonder on some images from the history of the bicycle. Here are the images, with some of the things the group noticed and wondered, followed by some comments from me.

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The Mysterious Bicycle Tracks

Audrey led the group through a classic problem which allowed us to use sidewalk chalk and ride bikes.

August’s CAMI meeting began with the following story:

You are brought to a crime scene. You are told that a thief just made off with a bag full of diamonds, escaping on a bicycle. You come across the following pair of bicycle tracks in the snow, no doubt made by the fleeing thief. But which way did the thief go?

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Skellzies!

Ramon had his students work on research projects, sharing their cultural backgrounds and relating them to mathematics. He shared the results of one student’s project and then led us into an exploration of the New York City street game called skellzies, skully caps, skellies, etc. (depending where and when you grew up in the city.)

When we walked into the room, this was on the board:

Teaching Problem: For three consecutive semesters, an adult education teacher began classes with roughly 36 students and ended with roughly 12 students. What can the teacher try that will help to reduce attrition?

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A Strange Algorithm

In our first evening meeting, Eric shared a web site that turns pairs of numbers in diagrams. But how does it work?

(This meeting was based on an underground mathematics lesson, Fawn Nguyen’s post and Michael Lawler’s videos. Thank you all!)

I started the meeting by showing the group the Picture This! web site that turns pairs of numbers into a diagram visualization. I asked for a volunteer to give me two numbers, each less than 10. The first suggestion was 3 & 7. I entered the number into Picture This and this diagram was returned.

3 & 7

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The Wet Iphone Task

We explored a problem related to volume and surface area with multiple solutions. But wasn’t one of them more right than the others?

–Updated April 2, 2021 to remove the Wet Phone task published originally in Middle Grades Geometry and Measurement (Steele, 2006). Our apologies to the author Michael Steele for posting your intellectual property.–

Cynthia started today’s meeting by saying that she would be sharing a problem from a recent workshop she attended on multiple solution tasks (MSTs). These problems are designed so that there are multiple correct solutions. In our math circle, we have grown accustomed to seeing multiple strategies for solving a problem, but usually there is one correct solution. Even after we saw different solutions later on, there was something nagging at me. Are they both equally correct? Really? Continue reading “The Wet Iphone Task”

CAMI Roadshow: 2018 NYC Adult Basic Education Conference

NYC CAMI revisited the Grid Power problem and modeled the collective problem-posing/problem-solving process of CAMI meetings.

At this year’s NYC ABE Conference, Jane, Eric and Mark brought back the Grid Power problem from the summer 0f 2016.

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Mondrian Art Puzzle

CAMI plays around with a way to practice multiplication, think about area and extend into algebra and generalizations. Through art!

For our final CAMI meeting of 2017, I wanted to spend some time at a CAMI meeting doing some math that would create some thing visual and beautiful. As I was looking around for activities to bring to the group, I came across the website, Math Pickle (as in “Put your students in a pickle”). They had a trove of math problems that I look forward to exploring in future CAMI meetings. The one I chose for this one is at its core an opportunity for students to practice multiplication in a way that is much more engaging than just memorizing facts and doing worksheets. And it builds works of art. As I started to play around with it, I started to notice different ways to think about how to make designs with the best score. Continue reading “Mondrian Art Puzzle”

Can you fit more boxes in a shipping container than Jane can?

Exploring some of the mathematics in packing a shipping container.

For today’s CAMI meeting, Mark was trying out a draft of a lesson that he wrote with Eric involving volume and units in a workplace context. The problem we explored involves trying to fit rectangular boxes into a shipping container.  Continue reading “Can you fit more boxes in a shipping container than Jane can?”

Growing Rectangles

This task, from Mathematical Mindsets, by Jo Boaler, asked us to explore how area and volume are affected when shapes are scaled up in size. For example, if you double the dimensions of a square, how is the area affected? What if you triple the dimensions?

We used this meeting to explore a problem from Mathematical Mindsets by Jo Boaler. I had worked on it a few weeks ago as part of an online book group with LINCS. I decided not to give out all the questions in the task at once, but you can look at the problem URL above to see the whole thing. Continue reading “Growing Rectangles”

What Do You Do with a Dizzy Sailor?

CAMI often goes back and forth between problems that challenge us as problem-solvers and those which we could use to develop problem-solving in our students. At this meeting, Solange bridges the divide and does both.

Solange led us in an exploration of two problems – first, the Dizzy Sailor Problem and then the Perimeter of 18 Problem. The former was to challenge and deepen our own problem-solving. The latter was to have a discussion about how some of the math from the dizzy sailor connects to the perimeter of 18, which we all agreed was a problem we could do with our students. Continue reading “What Do You Do with a Dizzy Sailor?”