I've really enjoyed solving the puzzles in Euclidea, a brilliantly designed app for iOS and Android. The basic format is "given this, construct that". You start with just two tools: a straightedge and a slack compass (i.e. a compass that does not remember the radius it was last set to). As you find useful and… Continue reading Stumped by Euclidea

# Tag: Technology

## More on Geometric Construction

(To search from previous posts on this topic, use the Search box on the right.) I suspect that by far the most common introduction to geometric construction in US classrooms is a presentation by the teacher (or textbook) on various compass and straightedge construction techniques. "This is how you construct a perpendicular bisector. This is… Continue reading More on Geometric Construction

## Calculation

Many students have weak arithmetic skills. Many teachers blame this on calculator use, but it is just as likely that the real reason lies elsewhere. For one thing, the teaching of arithmetic traditionally does not involve developing any understanding, so the learning is shallow and fragile. For another, students correctly feel that mindless arithmetic is… Continue reading Calculation

## Geometry Boot Camp!

I will offer two workshops this summer (2017), at the Head-Royce School in Oakland, CA. Sign up for either or both! June 26-27: Hands-On Geometry (grades 6-10) June 28-30: Transformational Geometry (grades 8-11) If the times or locations don't work for you, I can offer a workshop for your school or district. Contact me directly.… Continue reading Geometry Boot Camp!

## Upcoming presentations

I have a bunch of presentations coming up. That will be your last chance to hear me for a while, as my NCTM San Antonio talk was rejected†. Who knows, maybe retirement will finally kick in!Online Webinar: Reaching the Full RangeAs everyone knows, students learn math at different rates. What should we do about it?… Continue reading Upcoming presentations

## Reading Algebra

Symbol sense is an essential part of mathematical literacy. It is the understanding that undergirds effective symbol manipulation, and perhaps more basically the ability to interpret and create algebraic expressions. Symbol sense, like number sense and operation sense, is not learned so much through listening to a teacher. Rather, it grows as one gets practice… Continue reading Reading Algebra

## Eclectic

In between June 27 and August 4, 2016, I presented seven to ten workshops (depending on how you count) ranging from a couple of hours to four days. I share most of the handouts, resources, and slides on my Summer Workshops site. (See below my signature for more details on what's there.)The site will remain… Continue reading Eclectic

## Making a Vector in Desmos

A couple of years ago, during a workshop on transformational geometry, a participant objected when I used and recommended GeoGebra and not Desmos. Her main argument was that students love Desmos. Fair enough, but that does not make up for the fact that Desmos is mostly about graphing, while GeoGebra includes the many basic and not-so-basic… Continue reading Making a Vector in Desmos

## Visual Algebra

I will be teaching two instances of my Visual Algebra workshop this summer: grades 7-11, June 27-30, in Oakland; and grades 6-9, July 25-27, in Saint Louis. (More info). This is probably the topic I have presented the most often in the last 25 years.To many students, not to mention teachers, parents, and administrators, algebra… Continue reading Visual Algebra

## Animated Demonstrations

New on my Web site:→ Animated slides on the Lab Gear model for signed number arithmetic.Note that for each operation, the model is based on what students already know. For addition, you put down the first number, then the second number, and finally count. For subtraction, you put down the first number, take away the… Continue reading Animated Demonstrations