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Guest Post: Looking at Student Work with MathMistakes.org

Guest post by Justin Reich, cross-posted at Justin’s blog at Education Week (here).

In my Introduction to Education class, one of my goals is for students to get a sense of the value of looking at student work. Not just glancing at it, reading it, or grading it, but really trying to understand what we can learn about students’ thinking by examining their performances. In this post, I want to share one lesson that I did with my pre-service teachers in the MIT STEP program, using resources from MathMistakes.org.

MathMistakes.org is a project by one of my favorite bloggers, Michael Pershan, a recent winner of the Heinemann Teacher Fellowship. The URL says it all, MathMistakes.org is a collection of annotated math mistakes, submitted by teachers with comment threads that attempt to get inside student thinking and propose teaching solutions. Michael was a huge help in finding some great content for my lesson, including three juicy problems (natural logsexponents, and simple equations) with really interesting conversations in the forums.

Before showing the student work, I give my pre-service teachers a framework for thinking about looking at student work. In particular, I encourage them to start low on the “ladder of inference.” It’s very easy when looking at student work to jump to judgments and conclusions, and then make observations about work that support your first hunch. I think a more valuable approach is to start by making observations, keeping an open mind, and then moving towards conclusions.

 

Looking at Student Work

To help model that kind of thinking, I shared a Looking at Student Work Protocol published by ATLAS, that I think does a nice job guiding students towards that kind of thinking. A “protocol” in this context means a set of steps for addressing a situation. The ATLAS protocol is probably more designed for looking at more in-depth performances than answers to a few math problems, but it works as a good foundation.

In the ATLAS LASW protocol, people start by examining student work and just noticing facts about it, trying to avoid making any kind of judgments or inferences. Ideally, observers assume that the student producing the work is making their best effort in good faith. When looking at student work, it’s usually a distraction to assume that kids are being lazy or obstinate. Better to assume that they are putting forth their best effort.

The next step is to start asking questions about the work. What do you think the student is working on here? From the student’s perspective, what are they trying to do? Then, observers start making some judgments about the work and suggesting changes to the instructional environment or approach that might address issues that appear in the work. So eventually, we get to making judgments and proposing solutions, but we get there slowly.

In-Class Protocol with Math Mistakes

I modified that protocol to take advantage of the great resources at MathMistakes.org. Here’s what we did:

1)   Look at three problems on the board. Predict all of the mistakes that students might make.

Michael gave me three problems to work with, and before showing any student work, I showed my pre-service teachers the original questions and problems. I asked my students to predict the different kinds of mistakes young mathematicians might make. I put students into three groups (of about 8 teachers each), and I ask them to consider all three problems.

2)   Look at what a student actually did. Make observations about their work, first. Then, start to ask questions about what you see. Then, start to make some predictions about what they may have been thinking.

For this section, I assigned each group to look at one problem. One issue that emerged here was that different Math Mistakes have different richness of student output. For instance, one problem just showed that a student wrote the number 0. Not much to observe there. Another problem showed several steps of work, including some non-standard notation that lends itself wonderfully to close parsing. So some groups raced through the step of making observations, whereas other groups needed more time.

3)   Enrich your conversations by bringing in voices of expert teachers from MathMistakes. What new ideas emerge here? What is the range of possibilities of what the student may have been thinking? What is the range of ways to respond?

When group conversation started to slow (pretty soon for the group whose student answered “0”), I gave them each a printed copy of the relevant comment thread from MathMistakes.org. I printed them in part for logistical reasons (the class didn’t need computers for anything else), and in part because I wanted them to be impressed by the heft of the discussion. The comments for the three problems I shared run 10 pages long, filled with insightful observations about student thinking, analogous mistakes, and instructional approaches. My sense was that students were quite impressed that a single mistake on one worksheet could generate so much thoughtful reflection from experienced educators.

To wrap up, we shared a bit about what we thought was happening in each problem, what students might be thinking, and how we might remediate. Mostly, we reflected on how a single problem could be such a deep window into student mathematical thinking and the complexity of teaching responses. 

Thanks again to Michael for helping me pull these materials together!

We’ve clearly got some work to do here to make the materials on this site more helpful for teachers, pre-service teachers, and students, and Justin has helped tremendously. Take to the comments with ideas on how to use student mistakes to even greater effect.

Categories
Pythagorean Theorem Right Triangles Similarity, Right Triangles and Trigonometry Trigonometry

30/60/90 Mistakes

Right Triangle Quiz Responses

 

This is fairly representative of the class’ work. What would your next step be with this class?

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Multiplication Numbers & Operations in Base 10

Getting Better At Multiplying Two Digit Numbers

Previously, I shared my 4th Graders strategies for multiplying two-digit numbers. That work was taken at the beginning of our unit, and it’s interesting to me to follow up that post with an update of how their multiplication strategies developed over the course of the past two weeks.

MH RK-B SS ZG AB CD

Categories
Area Circles Geometric Measurement and Dimension High School: Geometry Similarity, Right Triangles and Trigonometry

Area of a Circle, Minus a Square

photo1

 

Do you see the mistake? How would you help this student?

Categories
Multiplication Numbers & Operations in Base 10

13,234 times 187

IMG_3460

 

What’s this kids next multiplication strategy? How would you help him get there?

Categories
Multiplication Numbers & Operations in Base 10

Multiplication Strategies My Students Are Starting With

Here’s the breakdown of student thinking about double-digit multiplication that I’m seeing as we begin our unit in my 4th Grade class.

Direct Modeling:

Directly Modeling

 

Direct Modeling With Composition Into Groups:

Composing

 

Breaking The Numbers Apart With Addition:

Breaking The Numbers Apart

 

Breaking The Numbers Apart 2

 

Breaking The Numbers Apart With Arrays:

Arrays Arrays - Breaking Numbers Apart

 

Use of Standard Algorithm:

Standard Algorithm Standard Algorithm - Wrong

 

No Real Strategy, But Knowledge Of Multiplication by Multiples of 10:

Not Sure

Categories
Multiplication Numbers & Operations in Base 10

15 x 12 = 20

securedownload-2

 

This comes via submission. Thoughts?

(“Algorithms unteach place value.”)

Categories
Distance Between Points Geometric Measurement and Dimension

The distance between (1,1) and (4,5) is 7

IMG_3378

Categories
Multiplication Numbers & Operations in Base 10

34 x 68 = 98

IMG_3364

Categories
Decimals Numbers & Operations in Base 10

Early Decimal Difficulties

IMG_3362

 

Write down 0.1, and add a tenth to it. Write that number down. Then add 0.2 to 0.1. Write that down. Then add one to 0.1.

In case it’s hard to see, in response to “What’s one tenth added to 0.1?” these students responded

  • 1.1, then crossed out with a “2” written over it
  • 0.01
  • 0.11

When asked “What’s 1 added to 0.1?” they responded

  • 0.2
  • 0.2
  • 1 0.1 (which looks like a mixed decimal to me which is pretty cool)

I’m trying to think through what class looks like tomorrow. It seems that I’ve got kids who certainly need time to work with 0.1, 3/10, 0.4 and other tenthy ideas. I also have students who don’t really have much of a grasp on how to use the hundredths place.

I’m going to take a page out of “Extending Children’s Mathematics” and give kids a version of this problem tomorrow:

Francine is making chili. She adds .1 grams of her secret ingredient to each liter of chili that she makes. If she has 5 grams of her secret ingredient, how many liters of chili can she make?

But what numbers would be most helpful to use in this problem? I’m struggling with that question right now. It seems like anything involving 0.1 or any tenths would be good, I guess. I think it’s probably most important for these students to relate decimals to whole numbers.

…and then the more practical concerns arise. What do I do for the quick finishers? They’ve done a lot of problems like this — will this problem feel tedious to them? Should I retrench with some of the part/whole stuff that we worked on yesterday? Maybe spend the first half of class solving chili problems and plan for a discussion, and then try this shading in activity again during the second half? Ooh, we could structure the second half of class around comparing 0.25 and 0.3, like my textbook says, or maybe the kids won’t be ready to discuss decimals that go into the hundredths…