Reasoning

The Slinky Task – FAQs

The Slinky Task was dropped a couple of weeks ago and I’ve spoken to a number of people who had a lot of questions about it, so I’ve added some interesting facts (FAQs) about this task below. Enjoy.

  • How did you come up with this idea for the task? I was at a nearby school last fall working with one of the teachers there and a friend of mine, who also works there, mentioned that some students were eating lunch in her room and one of the boys was playing with a slinky that she had. He actually said, I wonder how far this slinky will stretch. She said she immediately thought of me. And then I showed up the next day. It did take me a couple of months to figure out how I wanted to do Act 1.
  • How long did it take to straighten the slinky? The initial straightening (what you see in the beginning of the Act 3 video) took about 45 minutes and the slinky still had a lot of fairly sharp bends in it (see below) . It also gave me several blisters on my thumbs and a couple of fingers. Lesson learned: Wear gloves.
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  • So, how long to straighten the slinky after that? It took about 18 hours. I worked at it for about 2 hours a day, when I could. There was a huge learning curve involved. I made several mistakes that added to the time needed to get this done. It was tedious, but with music playing in the background, it was fine.
  • What tools did you use to get the slinky straightened? As I mentioned, there was a huge learning curve. Some of the suggestions I got from Google searches actually prolonged the work, so I eventually just clamped the slinky in a vise and used pliers and vise-grips to bend it a couple of inches at a time.
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  • Any surprises? Yes. The slinky actually snapped three times as I straightened it. This was not good, but I did come up with a way to hide this in the Act 3 video. I clamped the slinky to the measuring tape using vise grips in multiple places to keep it aligned. Those vise grips are strategically placed to hold (and hide) where the slinky broke.
  • Did anything else not work out the way you thought or hoped? Yes. After I straightened the slinky, I asked my son to help me get it measured. We got it clamped and everything was set, but the measurement wasn’t even close – I think it was about 2 feet off from what I had computed the length should be. I kept thinking that I didn’t straighten the slinky enough, so I kept trying to get more of the bends out. I wasn’t going to even share this task – even after all the time I spent on it – because the numbers just weren’t even close to the real world measurements. Then it occurred to me that maybe my reasoning and computation was wrong. I was so close to this. Maybe I wasn’t seeing something that I needed to see. So, I sent the unfinished task and my mathematical thinking to some math friends and colleagues. I thought some fresh eyes (and minds) might be able to see what I couldn’t. The next morning, I got an email back from @KCwetna, with just the right amount of wondering that helped me reason through my own thinking to find the mistake. And, this mistake she provided me with is now included as a part of the task. It introduces another level of thought for students as they engage in the task – all based on the wonders she shared. Brilliant! So, essentially, my mistake ended up making this whole task better with some help from my friends.
  • What’s next? When the idea for this task was shared with me, I initially thought about doing this for slinky jr and the giant slinky. As of right now, those are on the back burner, but would be great sequels to explore and they are suggested at the end of The Slinky Task. I do have the slinkies for these tasks, but haven’t started the sequels yet.

What is Mathematics?

In my previous post, I shared my personal experience with playing with mathematics as a child. That reflection prompted some digging about when we as humans begin to think mathematically, and I found something fascinating:

Experimental research shows that infants as young as 6 months have the ability to:

  • recognize the approximate difference between two numbers
  • keep precise track of small numbers, and
  • do simple subtraction and addition problems.

And when babies are mathematizing like this, they activate the same parts of the brain that are associated with mathematical thinking and reasoning in adults (I told you this was fascinating). So, before we can even speak, we have the ability to quantify. Our inherent curiosity and ability to think and even reason mathematically is on display here.

The idea that teaching and learning mathematics isn’t just computation, that it involves sense-making through reasoning, is research-based and builds on the natural curiosity, and the mathematical ideas and abilities we possess at a very young age. 

Mathematics helps us make sense of and explain the world around us. It is the science that deals with the logic of shape, quantity, and patterns. Mathematics is a subject created based on the need to solve problems and, in my opinion, should be taught that way. It’s a beautiful, creative, and fascinating subject with applications in every field: teaching, economics, engineering, biology, chemistry, physics, entertainment, shipping, food service, geography, geology, technology, real-estate, and politics, to name just a few.

The common myth is that mathematics = computation. While computation is embedded within mathematics, it is really a very small part of a greater whole. The strong, flexible core of mathematics is all about reasoning and sense-making. The “computation part” of mathematics can be taught with this strong, flexible core in order to make sure that the computation students learn makes sense so that it can be applied to solve problems in the real world. 

Ultimately, mathematics is about sense-making. The mathematics we use today to solve problems was developed by creative thinkers who asked questions like. “What if…?” “Maybe we could try…?” and “I wonder what would happen…?”  This creative thinking is still happening today to solve problems like coastal erosion from tropical storms. You, your students, or your children can be one of these creative thinkers that uses mathematics and mathematical modeling to solve some of the world’s biggest problems. Let’s keep students thinking about mathematics as much as possible!

Finding the Greatest Product – 5th Grade Students

This is a lesson from several years ago, that I borrowed from a post from Fawn Nguyen.  Her blog post describing how she used it is excellent!

In this lesson, students are given 5 digits and their goal is to find the greatest product without actually doing the computation. The fifth grade students I used this with loved it. We took two days – one day to introduce the problem and a second day to try it again with different numbers, and find patterns. This is a fantastic problem because of the connections to so much more than place value!  

Day 1

I started out with the same numbers Ms. Nguyen used in her example on her post.  I did this because of time constraints on the first day. PTO performance dress rehearsals can really mess up a plan!

So the students were given the digits 8, 2, 4, 5, and 7. The task was to create two factors that would give the greatest product without actually doing the multiplication.

I asked students to take 90 seconds to think about it, then share their ideas with their groups.  The math discussions were incredible.  “582 x 47″ is less than hers because 582 x 74 has to be bigger.  That one has only 47 groups of 582.  This one has 74 groups of 582!”  Similar comments/discussions happened at each table.

The students then shared their ideas for the two factors that would make the greatest product as I wrote them on the board:

582 x 74 =                                      782 x 54 =                                      872 x 45 =

 

825 x 74 =                                      752 x 48 =                                      752 x 84 =

 

                        754 x 82 =                                      572 x 84 =

I asked students to look carefully at their list and discuss with their tables which two they think should be removed and why. I did remind students that they should base their decisions on mathematical reasoning, not computation.

After about 90 seconds of discussion, I asked each table to identify the problem they think should go. After two tables shared, everyone agreed that these two (in red) should go.

582 x 74 =                                      782 x 54 =                                      872 x 45 =

 

825 x 74 =                                      752 x 48 =                                      752 x 84 =

 

                        754 x 82 =                                      572 x 84 =

The students’ reasoning ranged from rounding to doubling and halving to just finding one more on the list that had to be greater. After that, students had to decide from the 6 left, which one would produce the greatest product. Most groups eliminated 2 or 3 more, but they struggled to find 1 because they thought it could go either way (see the green problems above).

Again, due to time constraints and PTO rehearsals, I asked them to choose one. The classroom teacher who was observing, had already found the products of all of the problems on the board.  We asked for the products and wrote them on the board to some cheers of “Yes!” and some groans of “No!”

All agreed that it was a fun exercise. I loved it because the students were engaged in several of the mathematical practices, specifically constructing viable arguments and critiquing the reasoning of others This happens in other lessons, for sure, but it seemed more natural here because the disagreement was based on the reasoning used. Since not all students think the same way (and they shouldn’t), there were natural mathematical arguments discussions.

Before I left the classroom, I pulled out my deck of cards and had 5 students choose a number card to generate 5 new digits so that when they finished their PTO performance later in the evening, they could think some more about the math we did in class today.  They were asked to come up with a 3-digit factor and a two digit factor that they think would give the greatest product.

Day 2

The next day, we went through the same process (the previous day’s work was on the board for them to refer to).  The numbers the students drew were: 2, 9, 6, 7, 8

There were 12 ideas for the greatest product this time.

892 x 76 =                                      782 x 96 =                                      982 x 76 =

 

987 x 62 =                                      267 x 89 =                                      762 x 98 =

 

769 x 82 =                                      862 x 97 =                                      872 x 96 =

 

872 x 69 =                                      972 x 86 =                                      962 x 87 =

Again, I asked them to think for 90 seconds on their own, then share their thoughts with their tables about which problems could be eliminated based on mathematical reasoning.  After sharing, I asked each table for their thoughts about which should go and why.

Again, the reasoning was amazing. The class, as a whole, came up with reasoning to eliminate 8 of the 12. They’re shown below in red.

892 x 76 =                                      782 x 96 =                                      982 x 76 =

 

987 x 62 =                                      267 x 89 =                                      762 x 98 =

 

769 x 82 =                                      862 x 97 =                                      872 x 96 =

 

872 x 69 =                                      972 x 86 =                                      962 x 87 =

The class got into a discussion about which of the remaining should go without prompting because they were so engaged in this problem! The class could not decide, but it was pretty well split between the green problems above.

Some thought it was 862 x 97 because:

  • “It’s almost 100 groups of 862 and 872 x 96 has one less group of a smaller number, but it isn’t enough.”

The other group countered with:

  • “We still have almost 100 groups of a larger number.  We have one less group, but we have 10 more in each group!”

Again, the teacher was ready with the products and we checked all of the eliminated problems first to justify their earlier reasoning.  We heard a few things that really made these two days worth it like: “See, I told you it was about 27,000” and “We were right get rid of that one!”  Makes your heart swell up when kids say those things with mathematical confidence!

When we got down to the final two, they were on the edge of their seats! As the final products were revealed, there were no “I told you so’s” or mocking of others. The students really enjoyed the productive struggle of thinking and reasoning about greatest products. The students had a great time, but it wasn’t over yet.

As some in Queen Nguyen’s class, one student noticed a pattern from the work of both days.  His explanation is described below:

“I noticed in both problems that the 2 was in the same place (red underline) and that it’s the smallest of the digits we used, so I thought about the largest numbers (digits) and checked to see if they’re in the same place and they are (Blue underline)!”

Another student chimed in with “There’s more. Look, the greatest digit is in the tens place for the second number. The next greatest digit for the first problem is 8 (green underline) and it’s in the hundreds place. For the second problem, the next greatest digit is 7 (green underline) and it’s in the hundreds place, too! And the third? greatest digit is right next to that in the tens place of the first number. And the digit before the smallest is in the ones place of the second number.”

The students were eager to check another set of numbers to see if this pattern they found could actually be a mathematical discovery. They wanted 5 more digits to use to check – they were asking to do more math! Before they left for the day, I found out that some students wondered if the pattern would change if it was a 4 digit times a 3 digit. Guess we’ll have to do another exploration!

All of this stemmed from asking students to reason about multiplication. In the process, all of their ideas were used to build a deeper understanding of multiplication and estimation. As a result, they made an interesting mathematical discovery based on the patterns they discovered and posed a new question to explore!

Thanks, again, to Fawn Nguyen for sharing this problem!

Desmos Math Addiction

Hi, my name is Mike… and I love using Desmos with students.

This is not a bad thing at all.  I’m not giving up time with my family to spend on Desmos. It’s just that whenever I think I’ve exhausted all of the ways to use this fantastic tool with students, the Desmos team adds a new activity or game that I can and want to use right away!  These people know how to keep us wanting more!

Here you can find out what Desmos is all about!

Now, for all of you teachers out there that haven’t engaged your students in this amazing math tool, let me move from a user to a pusher.  4 reasons why you should use this amazing tool with your students:

crazy about math

  1. It’s completely free!  (not just this first time – all the time)
  2. It’s a graphing calculator that works beautifully online or as an app for students to Model with Mathematics – SMP 4.

This is a screenshot of how my son, Connor, used the Desmos Calculator to make sense of transforming quadratic functions.

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3.  When you sign up as a teacher (again, for free) you can assign activities and games (yep, they’re all free to use, too) to your students and you can check their progress from your teacher page.

So, beyond the graphing calculator – which is amazing on its own – as a teacher you can assign an activity to your students based on the content they are investigating. Try Central Park  – it’s my favorite activity.  (If you like, you can go to the student page and type in the code qqbm.  I set this up for anyone reading this post. Feel free to use an alias if you like).

And as far as games go, check out Polygraphs.  It’s like the Guess Who? game for math class. Trust me, your students will love it and there are polygraphs for elementary as well as secondary. The polygraphs are all partner games, so students will need to work in pairs.  I’ve even made a few:

Polygraph: Teen Numbers

Polygraph: Inequalities on a Number Line

Polygraph: Geometric Transformations

4.  As you get sucked in to this tool, you may begin to think to yourself, “Boy, I really wish there was an activity for ______.  If only knew how to create an activity for my students to use on Desmos.” That’s taken care of, too, with Activity Builder and Custom Polygraph (and, yep, you guessed it – they’re free to use, too)

And before you begin to doubt whether you can create an online activity or polygraph, the Desmos team has already taken steps to make this extremely teacher friendly.  Before you know it, you’ll have your own Desmos activity published!

Finally, as a great end of year gift, Dan Meyer blogged about the latest from Desmos – Marbleslides.  If this doesn’t get you to use Desmos with your students. . . well, I’m sure they will think of something else, soon. But seriously, try this out.  I have re-learned and deepened my own understandings of mathematics by trying and reflecting on many of these activities and games, and then having my own kids do them (and then they ask me why their teachers aren’t using them – “Can you talk to them, Dad?”).  The conversations will be happening this semester for sure!

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But the best part about all of this is that students get to use the calculator to investigate graphs and compare graphs and equations/functions.  They get to notice and wonder about what matters and what changes a graph’s slope, and y-intercept for linear functions and what changes the vertex and roots of parabolas.  They get to investigate periodics and exponentials and rationals and so much more.  They get to engage in activities and games that have components that ask them to reflect on what they’ve learned in the games and activities themselves.  The students are doing the mathematics.

Then, in class, we get engage students in talking about the math they’ve investigated!  How sweet is that?

You see, as great as Desmos is, it can’t take the place of great teaching.  It’s a tool that can help us become better at our craft and help our students gain a deeper understanding of mathematics!  Sounds like a win-win!

So, I guess I don’t have a Desmos math addiction.  Addictions have adverse consequences and I see none of that here!  I just have – as we all do thanks to Desmos – access to a powerful mathematical learning tool!  Thank you Desmos.  I can’t wait to see what’s coming next!

Unlikely Students in Unknown Places

I recently got back from Santa Fe.  I was attending a conference there for a few days last week and afterward, I drove to El Paso to visit my brother’s family (he’s currently stationed in the middle east so I didn’t get to see him – unless you count face time) for a day before flying home.

Let me preface this story by saying that we all probably have a story similar this, but how we handle it can be a possible game changer.

Somewhere on my long drive, I stopped at a fast food restaurant to grab a quick bite.  So, I went inside and got in line.  The following outlines the beginning of our interaction as I stepped to the counter:

Cashier:  May I take your order?

Me:  Yes, please.  I’d like a number 2.

Cashier:  Large or medium.

Me:  Medium, please.

Cashier:  (after pushing more buttons than is conceivably necessary to enter my choice of “medium”): Your total will be $6.05.

I dug through my wallet (receipts from the trip and everything) and found that all I had was a $10 bill, so I handed it to her.  She entered $10.00 correctly and the correct change of $3.95 showed up on the little screen.  At just about that point, I remembered that I had a bunch of change in my pocket and said quite enthusiastically, “Oh, wait, I think I have a nickel.”  Who wants to carry around $0.95 in change in their pocket.

The cashier didn’t miss a beat, and said, “So, your change will be $4.00 even.”  I kind of smiled as I continued to look through my change, proud that she had a mental strategy to adjust to the situation and that she seemed quite confident and comfortable using it in this situation.

Unfortunately, I didn’t have a nickel, but I still didn’t want change falling out of my pocket into the depths of the rental car, never to be seen by me again.  So, I told her, “Oh, I’m sorry, I don’t have a nickel, but I do have a dime.”

As I handed her the dime, I saw her face morph from a confident smirk to a confused, almost terrified look of despair .  I had just taken her from a mathematical point of “Yeah, I can do this math stuff.  I may not use the computer for the rest of my shift” to “Holy $#!+, what the #=|| just happened!”

I went into math teacher mode and waited patiently for her to begin breathing again.  And then I waited for her begin thinking.  She adjusted my change with my introduction of the idea of a nickel, why not a dime? After what seemed like 5 minutes (probably more to her), it was painfully obvious to all around that her anxiety in this situation was taking over her ability to tackle this problem. So, I tried to think of a “least helpful question” to ask.  Now I put myself on the spot.  If she only knew that we were both now feeling some of this pressure.

So, I finally asked her my question and she gave me the correct change within a few seconds.  She smiled as she gave me my change and my new “unknown” student and I parted ways.  I know I felt good about helping someone develop a strategy outside of the classroom.  I hope she had a similar feeling about learning to make sense (no pun here) of making change.

Being a math teacher is a 24-7 job sometimes and we can find our students anywhere – even in a fast food restaurant in New Mexico!

What you would have asked the cashier in this situation.  I’d love to hear what your “least helpful” question would have been. No pressure, take as long as you like.  No one is waiting in line behind you!

Feed the hungry!

Oh, here’s my question:  “If you could change the dime into some other coins, what would you change it for?”

Connecting Percents and Fractions

Not understanding mathematics can be extremely frustrating for students.  As a teacher, figuring out how to help students understand mathematics can be just as frustrating.  My primary go-to resource for these situations is Teaching Student-Centered Mathematics, by John Van de Walle et. al.  because it’s all about focusing on big ideas and helping students make sense of the math they’re learning in a conceptual way.

Recently, I was asked to model a lesson for a 6th grade class who was having difficulty working with percents.  So, I turned to my go-to resource, and during planning, I realized that I didn’t know anything about these students other than that they were struggling with percents.  So, I couldn’t assume anything.  I ended up creating three separate lessons and combined them into 1.

First, I handed groups of students a set of Percent Cards and Circle Graph Cards.  Their task was to match the percent with the corresponding circle graph.  As students were working on this, I heard groups reasoning about how they were matching the cards.  Many started with benchmarks of 25%, 50%, and 75%, while others started with the smallest (10%) and matching it to the graph with the smallest wedge.  As groups finished, they were asked to find pairs, using the matches they made, that totaled 100%.  Once finished, a discussion about their process for completing these tasks revealed a solid understanding of percent as representing a part of a whole.

Now to shake their world up a bit.  I asked them to leave their cards because they would be using them again shortly.  I introduced these Percent circles and asked them what they were.  A brief discussion revealed some misconceptions.  Some students said they were fractions, others said they were wholes because nothing was shaded.  I altered my planned line of questioning to questions that eventually led to a common understanding of what fractions were and how the pictures of the fraction (percent) circles really showed wholes and parts (fractions).

Their next task was to match their cards with the equivalent fraction circle.  This was incredibly eye-opening. Groups began to notice that some percent card matches could fit with multiple fraction circles (50% could be matched with the halves, quarters, eighths, and tenths).   Thirds and eighths were the last to be matched.  But their reasoning didn’t disappoint.  One group noticed that the percents ending in .5 all belonged with the eighths because they were too small to be thirds (the other percents with decimals).

Students were eager to share their thoughts about what they learned about fraction circles and percents:

  • Fractions and percents are the same because the pieces look the same.
  • 1/4 is the same as 25% and 2/8
  • I don’t get why the eighths end in .5.
  • The percents all can be fractions.
  • 1/8 is 12.5% because it’s half of 25%

Finally, I asked students to solve a percent problem (now that they’ve all realized that fractions and percents can be used interchangeably).   I gave them the m & m problem from this set of percent problem cards.  The only direction I gave was that they had to solve the problem using some representation of the percent in the problem before they wrote any numbers.

My bag of M&M’s had 30 candies inside.  40% of the candies were brown.  How many brown candies is that?

While this was problematic at first, students looked at their fraction circles and percent cards and realized they could use four of the tenths since each tenth was the same as 10%.  Most students needed just one “least helpful” question to get on the right track:  Where do the 30 m & m’s belong in your representation?

Most groups were able to make sense and persevere to solve the problem correctly, and explain why they “shared the 30 m & m’s equally among the ten tenths in the fraction circle” and why they “only looked at four of the tenths because that’s the same as 40%.”

My beliefs that were reinforced with this lesson:

  • We can’t assume understanding from correct answers alone.  We need to listen to students reason through problematic situations.
  • Students really want to share their thinking when they realize that someone is really interested in hearing it.
  • Students crave understanding.  They really want to make sense.
  • Procedures are important, but not at the expense of understanding.
  • Empowering students by allowing them to build their own understanding and allowing them to make connections allows students to feel comfortable taking risks in problem solving.

Please take a look at Jenise Sexton’s recent blog about percents with 7th grade students for some fantastic ideas about students using number lines and double number lines to solve percent problems.  It’s SWEET!

 

Perplexing Donuts

A good friend and colleague, Krystal Shaw, tweeted this article about Krispy Kreme Donuts in the UK a while back and it immediately got me thinking. . . so I really liked it and wanted to use it with kids.  To plan for the lesson, I started to take myself through this problem as if it were a 3-act task (I wasn’t sure it would become one, but I wanted to see where this would lead).  I looked at the picture:

Top of Box

and jotted down what I noticed. Then I began wondering:

  • How many donuts are in that big box?
  • What are the dimensions of the box?
  • Is there more than one layer of donuts in the box?
  • How many rows of donuts are there?
  • How big is (What is the diameter of) a Krispy Kreme donut?
  • When I was finished (or thought I was finished) wondering, I began to seek the information needed to answer my questions.

I found some nice strategies for determining the number of donuts in the box.  Strategies accessible for 4th grade students.  I was happy, so I moved on to the next question: What are the dimensions of the box?

This is when it happened.

I was stuck.

Perfect.

Challenge accepted.

I looked at the pictures, found the information in the article, then began to question that information (and myself) as well as some critical friends.  This problem was getting better and better as I walked myself through it.  Fantastic!  SMP 3: Construct viable arguments and critique the reasoning of others, such as a Krispy Kreme representative from the UK or a USA Today reporter.  Maybe this question won’t have a third act, but the estimation and reasoning used to solve this could be extremely empowering for kids.

I challenge you to solve this problem with your class as well and share your results.     Challenge yourself and your students to construct a viable argument and critique the reasoning of others.  Does your math challenge the information in the article or support it.  Either way, integrate writing into math class in a meaningful way:

write to the reporter, Bruce Horovitz or Krispy Kreme UK: helpdesk@krispykreme.co.uk and tell them what you  discovered

Time for me to give this a try!  More in about a week.

By the way:  Krystal Shaw gave her amazing Mathletes after school club the task of writing a 3-act math lesson for their teachers to teach.  I think she should post it on her blog to share with the MTBoS!

The Penny Cube

I just finished a 5th grade 3-Act task called Penny Cube that I created last spring.  I tried it then, but just to get some feedback from students and see what I might need to change about how the task should be presented.  Now, after completing this task with two groups of students (at two different points in the year), I’ve learned three things:

  1. Students see a video and notice a bunch of things that teachers don’t even realize are there.
  2. The curious questions students ask first are often “why” questions.
  3. There’s no way to predict everything a group of students might wonder.

I’ll take this reflection from the beginning.  First, I let students know that I was going to show them a video clip.  I also told them that I was going to ask them what they noticed when it was finished playing.  I gave students a chance to brainstorm ideas about what they could do to make sure they would be able to share what they noticed once the clip had finished playing.  Their ideas were amazing:

  • We could look for expressions (on faces – I found out later that this student was thinking about context.  A person’s facial expression can tell a lot)  Unfortunately, there were no facial expressions in this video.
  • Listen carefully (they might be able to hear something that might give them a clue about what was going on – these students were already expecting a problem situation!)
  • Stay focused on the clip.
  • Take notes.
  • Try to remember as much as you can.

I had never done this before, but after hearing their ideas, I will be using this again.

After showing the video clip for Act 1, I immediately had them talk about what they noticed with their groups.  Then, they were asked to share with the whole group.  Here is what they noticed:

Penny Cube Notices

What’s missing from this picture is the wonderful reasoning given for some of these.  For the last bullet, “container is open in the front,” the student told the class that it was open in front so the pennies could be placed in the container more easily (I never thought they’d see or think about that).  They even began to wonder a bit here – “it might be an expression or it might be counting.”  My favorite, though, is the estimation by the girl who said “it looks like 100 pennies in the stack ($1.00).”  This was particularly interesting to me because of what happened when they were asked to estimate for the focus question.

The wonders were typical from what I usually get from students new to 3-Act tasks, but I handled it a bit differently this time.  Here are their wonders (click here for a typed version of Penny Cube Notices&Wonders):

Penny Cube Wonders

In my limited (yet growing) experience with teaching using 3-Act tasks, I’ve noticed that the wonders are initially “why” questions (as stated in number 2 above).  I told the class that I noticed that the questions they were asking were mostly “why” questions.  I asked them what other words could be used to begin questions.  Rather than trying to steer students to a particular question, I decided to focus the students’ attention on the kinds of questions they were already asking, and guide them to other types of questions.  It didn’t take long!  Within about 5 minutes, students had gone from “why” questions to “how many . . .” and “how much . . .” questions which are much easier to answer mathematically.

The students were then asked to figure out what they needed to solve the problem.  From experience with this task, I knew that most students would want pennies, so I had some ready.  I didn’t give them the Coin Specifications sheet, because no one asked for it.  I did have it ready, just in case.  Every group asked for pennies and rulers.  I wasn’t sure how they would use them, but I was pleasantly surprised.

Here’s what they did:

How many pennies in 2 inches

How many pennies in 2 inches

How many pennies in an inch

How many pennies in an inch

How many pennies fit on a 6 inch edge of the base

How many pennies fit on a 6 inch edge of the base

How many pennies cover base

How many pennies cover base

How many stacked pennies in 2 inches?

How many stacked pennies in 2 inches?

 

 

 

 

 

 

 

 

 

 

 

The students all started in a place that made sense to them.  Some wanted to figure out how many in the stack, so they stacked pennies and quickly realized (as I did when filling the cube) that you can’t stack pennies very high before they start to wobble and fall.  So, they measured smaller stacks and used that info to solve the problem.  Others wanted to find number of pennies along an edge to find how many cover the base, then work on the stacks.  Students were thoroughly engaged.

After three 1 hour classes, students were wrapping up their solutions.  Some groups were still grappling with the number of pennies in a stack.  Others were finished.  A few were unsure about what to do with some of the numbers they generated.  All of this told the classroom teacher and me that there were some misconceptions out there that needed to be addressed.  Many of the misconceptions had to do with students disengaging from the context, rather than integrating their numbers into the context:

  • One group was unsure of whether to multiply  the number of pennies in a stack by 12 (6 inches + 6 inches) or to use 64.
  • Another group found the number of pennies to cover the base and multiplied it by itself to get their solution.
  • A third group found 37 pennies in 2 1/2 inches and was having a difficult time handling that information.
  • A fourth group had come up with two different solutions and both thought they were correct.  Only one could defend her solution.

Eventually, several groups arrived a solution that made sense to them.

Time to share!

I chose one group to share.  This group had a reasonable solution, but their method and numbers were different from many of the other groups, so this is where we were hoping for some light bulbs to begin to glow a bit.

This group shared their work:

20140919145046-3351215

 

 

 

 

 

 

 

 

 

 

I asked the class what they liked about the work.  The responses:

  • The math (computations) are written neatly and they’re easy to follow.
  • I know what their answer is because it has a bubble around it.
  • The question is on it.
  • It’s colorful.

All good.  Now, for the best part:

What questions do you have for this group?  The responses:

  • Where did you get 34?
  • What does the 102 mean?
  • How about the 64?

Any suggestions for this group to help them clarify their work to answer some of your questions?

  • Maybe they could label their numbers so we know what the numbers mean.
  • Maybe they could tell what the answer means too.  Like put it in a sentence so it says something like “6,528 pennies will fit in the container.”
  • Maybe they could have a diagram to show how they got a number like 64 or 34.  I know that would help me (this student had a diagram on his work and thought it was useful).

The light bulbs really started to glow as students began making suggestions.  As soon as a suggestion was made, students began to check their own work to see if it was on their work.  If it wasn’t, they added it.  All of the suggestions were written on the board so they could modify their work one final time.  The best part about this whole exchange was that students were suggesting to their peers to be more precise in their mathematics (SMP 6 – Attend to precision).  And, they really wanted to know what 34 was because they didn’t have that number on their boards (which is why I chose this group).

Now for the reveal!  When I asked the class if they wanted to know how many pennies were in the cube, they were surprised when I pulled up the reveal the video.  I guess they thought I’d just tell them (that’s so 1980’s).  They watched to see how close they were and when the total came up on the screen, many cheered because they were so close!

The students in this class were engaged in multiple content standards over the course of 3 days.  They reasoned, critiqued, made sense, and persevered.  It’s almost difficult to believe that this class was a “remedial” class!

Below, I’ve included a picture of each group’s final work.

20140916143126-1706895 20140916143218-1880868 20140916144859-1652302 20140916143241-1966871 20140916143157-1917874

 

 

 

 

 

 

 

Finally, one of the conversations witnessed in a group was between a girl and a boy and should have been caught on video, but wasn’t.  This group had an incorrect solution, but they were convinced they were correct, so to keep them thinking about the problem, I asked them how many dollars would be equal to the number of pennies in their answer (3,616).

  • Girl:  There are 100 pennies in a dollar.  So 600 pennies is . . .
  • Boy in group: $6.00
  • Girl (after a long pause):  1,000 pennies equals $10.00
  • Boy:  So that’s . . . um. . .
  • Me:  How does knowing 1,000 pennies = $10.00 help you.
  • Girl:  We have 3,000 pennies, so that’s $30.00.
  • Boy:  $36.00
  • Me:  Share with your group how you know it’s $36.00
  • Boy:  Because $30.00 and $6.00 is $36.00
  • Girl:  And the rest (16) are cents.  $36.16!

And they didn’t even need a calculator!

Math really does make sense!

How Old is The Shepherd? Revisited in 3rd Grade

Over the past few weeks, I’ve shown the How old is the shepherd? problem to both of my kids and then shown them the video  from Robert Kaplinsky’s blog. Both were shocked at how many students don’t pay attention to what is happening in the problem.  Connor even said, “I guess I’m not one of the 24.”

Here is my son, Connor, with his response to the problem:

Unfortunately, his first statement, “That’s stupid!” was not caught on video!

My daughter, Lura, with her response:

Last Saturday, after ambushing one of my daughter’s friends with the problem while she was visiting, Kim (my wife) became more curious about the problem, so I showed the video to her and shared some of the data on Kaplinsky’s blog. She was also shocked at the results.  We had a brief conversation that went something like this:

Me: This is why we need to teach math content through patient problem solving and sense making!

Kim: Ok. (with a look that says, I know you’re passionate about this, and that it’s important. We’ll talk later. Go make a 3-act video and post it to your blog.)

Me: Ok.

It was left alone until this morning. It’s just me, but I like to think we would’ve talked sooner if I hadn’t been fighting a cold. She texted me and asked me to send her the Shepherd problem. I did, but only with the requirement that she share what she does with it.

Kim (and her co-teacher) gave the problem to each of their students and I just received the results:

  • 3 out of 19 students made sense of the problem (15.8%)
  • One student added 125 five times.
  • One student reasoned that by the time you had 5 dogs and 125 sheep, you have to be in your fifties.
  • One student divided 125 by 5.
  • 6 students added 125 and 5 to get 130.
  • 3 computed an operation with the two numbers incorrectly
  • The other students guessed or showed no reasoning.

Now the good stuff:

  • One student (an autistic child) shared his reasoning about the problem with his classmates:

“The shepherd has no-o-o-othing (said as a sheep might say it) to do with the sheep and the dogs.”

  • Both teachers lost it!

Take aways from this:

  • It’s best that we start teaching math content through problem solving early and consistently K-12 and beyond.
  • Making sense of mathematics needs to be a priority for all students. (SMP 1)
  • All students bring something of value to a classroom.
  • Stories like the student who shared his reasoning sometimes get us through days that are not so much like this.

Below, you will find some of the students’ reasoning.

How old is the shepherd_

 

Are Your Students Doing Mathematics?

It seems like a silly question, really.  The answer, we would expect, is “Yes, every day!” Unfortunately, I’m not sure this is the case.

For those of you about to first step foot on the exhilarating math train that is teaching mathematics, it’s probably a good idea to share a few facts and myths about learning and doing mathematics.

Myths:

  • math is equated to certainty (sadly, this belief is held by many!)
  • knowing mathematics means being able to get the correct answer – quickly (again, this belief is held by many)
  • mathematical correctness is determined through the use of a teacher or an answer key.

Facts:

  • mathematics  is a science of pattern and order (this was taken from Everybody Counts)
  • math makes sense (teachers cannot make sense of mathematics for students)
  • doing mathematics requires students to solve problems, reason, share ideas and strategies, question, model, look for patterns and structure, and yes even fail from time to time.

If you walk into a math classroom – at any level – students are doing mathematics if you see/ hear students doing the following:

Explore Construct Justify Develop
Investigate Verify Represent Describe
Conjecture Explain Formulate Use
Solve Predict Discover Discuss

If teachers are doing most of these, a shift needs to happen.  All students can do these things.  All students can learn and do mathematics.  All students can make sense of mathematics because math makes sense.

As I reread what I’ve written so far, it tends to read a bit negative.  That was not my intent.  I just wanted to point out that wherever you are in the vast range of stakeholders of math education, please be aware that just because there are students in a math class, does not mean they are necessarily doing mathematics.  That wasn’t much better!

This might be a better way to end this post:

There are many of us (more than I thought when I first started this blog) who are making the case for teaching mathematics for understanding through engaging tasks.  Dan Meyer, Andrew Stadel, Fawn Nguyen, Graham Fletcher, Jenise Sexton, and Robert Kaplinsky, just to name a few, use their blogs to share their thoughts, lessons & tasks they create, and their thoughts on what it means for students to learn and do mathematics.  These, and many others, continue to push all of us to become a better math teachers.  Personally, they strengthen my resolve, knowing that our numbers are growing along with our minds and the minds of our students!