# Category Archives: Algebra

## Venturing Into the Sequel of Penny Pyramid

I didn’t get around to doing Penny Pyramid when I first saw it last year. But Dan‘s 3-post series and Nathan‘s recent mention of it were the reminders I needed to make it happen. Act 1 how many pennies how much money is that how long did it take who in their right mind would do this/who has that patience how much […]

Also posted in Geometry, Problem Solving | | 2 Responses

## When I Let Them Own the Problem

From our textbook: Stuff like this makes my heart sink. (I actually wrote that it makes me fart — but that’s very unladylike. And I’m trying to write better.) There is essentially nothing left in this problem for students to explore and figure out on their own. If anything, all those labels with numbers and variables […]

Also posted in Geometry, Problem Solving | | 30 Responses

## When I Got Them To Beg

A quick flip to the quadratics section in each of the six textbooks lying around here I find at least one problem about finding the width of some border. The concrete around a pool, the walkway around a garden, the frame around a picture, the border around a rug. I present to you the collage. […]

Posted in Algebra | | 13 Responses

## Des-man

Just how fabulous is Desmos. Following up on last Friday’s lesson, I had the kids create “Des-man” on Desmos. I made these very simple sketches, showed them to the kids, and told them the minimum requirements: face and mouth must be parabolas eyes and nose are linear equations Not only was this so great to reinforce slope, y-intercept, and all the coefficients, it also […]

Posted in Algebra | | 8 Responses

## Students Embroiled in Conway’s Rational Tangles

Me: We’re going to do an activity today. Jonathan: Let me guess. It’s your favorite activity. M: How did you know that? J: You say that about everything we do. M: You have a problem with that? J: No. But I’ve lost track of how many favorites you have. M: And I’ve lost track of how many […]

Also posted in Geometry, Problem Solving | | 5 Responses

## Stack ’em High

My algebra kiddos are doing Dan Meyer’s Stacking Cups because Andrew Stadel did the lesson and wrote glowingly about it. But Andrew used only one-size cups, I used three (that’s three!) different sizes. Who’s better now. Just eyeballing I ask students to look at me, look at this 12-oz Styrofoam cup that I’m holding, and estimate how many cups they […]

Also posted in Problem Solving | | 5 Responses

## The question was mine, but the answer was all his.

I carry a defective teacher gene that makes me intolerant of pacing guides and curriculum guidelines. I’m sure I’m a month behind in the pacing guide, and I’m pretty sure no part of today’s lesson will appear on any state test. But I did it anyway. The algebra kids have been doing a lot of […]

Also posted in Geometry, Problem Solving | | 1 Response

## Lego Pieces and Feasible Region

This afternoon I came across a tall stack of Lego® boxes stored in my son’s closet; they reminded me of a lesson. (My son just turned 20 three days ago. I can still see him playing with his Lego sets for hours on end when he was younger. And when he ran out of floor space […]

Also posted in Problem Solving | | 12 Responses

## More Rectangles and One Good Read

I just started reading this book on Ramanujan, and I highly recommend it. Curmudgeon just posted this Painter’s Puzzle yesterday on Christmas Day — what a nice gift for us! A painting contractor knows that 12 painters could paint all of the school classrooms in 18 days. They begin painting. After 6 days of work, though, 4 people were added […]

## Parallel and Perpendicular Lines

Bleh. I don’t know of a clever way to teach parallel and perpendicular lines. I’ll try asking kids questions and maybe their answers will guide me and make me look smart until 2:50 p.m. Me: Using your arms, show me parallel lines. They do. One boy clasps his hands together like he’s praying. M: What […]

Posted in Algebra | | 2 Responses
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