The Power of Visualization – Modifying Graphs with a Graphing Calculator

I have had some great discussions with teachers in my courses lately about the power of providing opportunities for students to see and manipulate mathematics as a way to test out their ideas, play with patterns, and develop their own rules and understandings. Visualization, manipulation, experimenting – all contribute to students developing deeper understanding and their own ‘algorithms’, and because of these contextual experiences, they are much more likely to recall how to do a math process than if they were just given the rules/algorithm to memorize.

In a recent final reflection, one teacher wrote, “As a high school teacher, I have always stayed away from using manipulates for fear they were “too elementary” for my classroom.”  This attitude – that older students don’t need those physical objects or need to see – that they just need to  memorize rules and practice – is sadly still prevalent today. Which is frightening really. I experienced these same attitudes and beliefs over 2 decades ago when I was teaching in  middle and high school, and bringing out my two-colored chips, algebra tiles, and Sketchpad. Allowing students to play with math, to use physical objects, and virtual objects, to represent the math and then be able to manipulate change and see what happens was always considered ‘babying’ them. Clearly that attitude is still going strong today, since as you read above,  I hear it in the courses I teach with current classroom math teachers. This despite even more tools being available to provide a way for students to experiment, play, discover, create and find the mathematical patterns and rules themselves. The tendency to just give them the rules and the process and the definitions and have them memorize and regurgitate is still very much a part of our mathematical education. What we really want to do is provide multiple ways to look at and explore math concepts, so that when students ‘forget’, they have that experience where they built the understanding to recall where they can rebuild it again. Much easier to recall something they saw or something they physically moved and connected to than an isolated, memorized fact.

In most typical high school classrooms I visit and work with these days, it is rare to find physical manipulatives (more often in Geometry, but much more rare in an Algebra 2 or Pre-calculus class for example). But – there is almost always a technology tool – whether that be the teachers projector attached to the internet, or students on tablets/laptops, or more often the case, graphing calculators of some sort. Which means there is no excuse NOT to be providing students the opportunity to visually see the mathematics, and to manipulate and explore to come up with those algorithms they are often asked to just memorize. Meaning: use the technology for more than checking answers!  Use it to help students find the patterns and connections and create their own algorithms and definitions, use it to delve deeper into the math, to gain insight, to test out conjectures and really get a sense of what all those numbers and variables mean and how they interact with each other to change the shape of a graph and what that might mean in a application of that math in the real world. Use the tools to manipulate and see the math; technology allows for students to test a conjecture quickly, make predictions and check if they are right, and explore very large and very small numbers, etc.

As an example of this, I am going to use the Graphing Calculator App (for mobile devices), since I haven’t previously used this before in any of my videos, to show the power of visualization and technology to make conjectures and immediately test them with modifying features/dynamic math capability. You can do this on our hand-held Prizm series graphing calculators  (handhelds and emulators).

 

Additional Note: Try our FREE new dynamic math software that is web-based – perfect for tablets, PC’s, mobile devices: ClassPad.net

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Classpad.net Version 1 – Just In Time for School!

Welcome back to a new ‘school year’ (for some anyway). I’ve been on a bit of a hiatus the last couple months, working hard and doing a bit of travel. But, time to get back to it and what better way to start things off but with the launching of Version 1 of Classpad.net.

I posted about Classpad.net back in May, in my post Classpad.net – My Math Love-Affair Continues, This time I want to actually delve much more into what Classpad.net is and share some activities and images to give you a sense of the power of this web-based software. We’ve been in Beta-mode, where we’ve been fixing bugs, working on functionality improvements, and other things while teachers and students have been playing around with the software. Big shout out to all of you who’ve been giving us feedback – we’ve been updating and making changes and fixing bugs in large part to your input. Today is the launch of Version 1, so no longer in ‘test-mode’. Does that mean it’s done? Absolutely not! The beautiful thing about web-based software is that we are constantly improving and updating and adding features. It’s really in its infancy, with so much more growth and functionality and improvement on the horizon, which makes it even more exciting knowing this is only the beginning.

What is Classpad.net?

Great question. At it’s heart, it’s FREE (yes…forever) web-based, dynamic, math software. We call it ‘digital-scratch-paper’ because you can pretty much do whatever you might do when you pull out a piece of paper – i.e. write some notes, do a calculation, make a graph, create a table, draw a picture, measure something. As we know, there are lots of math software and tools out there – but most have specific purposes (i.e. only do statistics, only graph, only do calculations, etc.), so we end up having to use one tool to make graphs, another tool to create geometry constructs, yet another one to do some statistical analysis. And then, if we want to create an assignment for students, we have to use yet another tool to copy-cut-paste our various tables, graphs, constructs, and directions into a usable document. Classpad.net allows you to do all of that on one ‘paper’, which can then be printed (PDF), or shared (unique URL), or saved.  You can send this to students via URL (email or post on your website), students can make their own copy and do their work and send it back to you. It’s all there on one page – and, the beauty is, you can arrange and rearrange things on that paper as you want. To the right is a snapshot of a ‘paper’ showing all the stickies – i.e. text, calculate, graph, geometry, table/statistical plot. You have unlimited scroll and vertical space, and all objects are moveable – arrange and rearrange to your hearts content. You can title the pages and change the banner color to help sort and group content areas.

What Are The Components of Classpad.net?

You can pretty much do all the mathematics you need with Classpad.net for all K-12 curriculum content areas, including Calculus and AP Stats. There are some features that as of today are behind a ‘paywall” (i.e. nominal fee for the add-on app feature), but these are features that most K-12 teachers would NOT want students to have or necessarily need (re: CAS ability, allowing for solving equations or factoring polynomials, as an example; handwriting recognition, and a few others as we add in functionality).  But, here are the general components of Classpad.net, and with each there is a quick GIF showing some aspect of each component:

TEXT – text is just that – you can pull up a text sticky to write directions (for student homework/tests) or descriptions. You can also type in mathematical expressions/equations/terms in the text. Text stickies can be moved and resized as needed, color changes, and you can set a sticky for students to respond to (or students can add their own text sticky to write in answers and reflections as they work on things.

 

 

 

 

CALCULATE – as you would expect, calculate does calculations and so much more. You can define functions and lists, and use them later in graphs and statistical tables. Due to natural display, you can get exact answers. You can use function notation and shortcuts (see the ? at top right of Classpad.net for the function list). And, as with all the stickies, you can move the calculation stickies wherever you need them to be or pull them up whenever needed – all on the same paper.

 

 

 

GRAPH – again, you can graph anything – equations, defined functions, inequalities, integrals, etc. You can create sliders to move graphs and compare functions. You can find area under the curve, click on the graph to see key points, add moveable points to a function plot, look at the table of values, or plot from a table a values, make moveable lines for lines of fit. Comparing graphs is easy too – you can put graphs together or pull them apart to look at things separately. You can have multiple graphs on your paper – either merged or separate. You can add pictures to your graphs as well.

 

 

 

GEOMETRY – Yep, you can even add geometry to your page. We are still building out the geometry component, but right now you can do what you would expect with a geometry tool – i.e. create geometric constructs and specific constraints (perpendiculars, parallels, etc.), measure (area, length, angles, etc.), transformations including dilation, with features that are also unique (so you can construct conics, you can draw free-hand and then ‘adjust’ shapes and objects to have particular constraints. There’s the ability to create a rotational slider. You can create Hide/Show buttons and functions and expressions, and of course typical things like hide objects and change size, colors, etc. I am excited about geometry because I know it’s only the beginning and there’s so much more we are going to be adding.

 

 

STATISTICS – So much to do already, and still so much more to come with statistics. But, what’s the most fantastic part is you don’t have to go get a ‘statistics’ tool for students to be able to collect data, record it in a table, and then analyze that data. This could mean measures of central tendency, or standard deviation, or making different statistical plots to represent the data. Normal distributions, many types of regressions, box-plots, dot plots, histograms…so much there already and we are adding more in the future. As you would expect, we have a spreadsheet that can do calculations or use pre-defined lists (see calculate). You can then add functions to your statistical plots – so everything is all in one place for students to explore and connect.

 

 

As you can see – there’s so much to do, all one one page and one platform (#one-stop-shopping) and it’s free! It’s designed to be usable on touch-screen devices and mobile-devices as well as laptops and PC’s. The perfect tool as you are preparing for this school year, or are just starting your school year (or maybe you are already in-deep to your school year….it’s never too late). Go explore and give it a try and make sure you are letting your student know about this tool. We are also building out our ready-to-use lessons and our video library of support, as we continue to add and improve functionality, so stay tuned. Check out our social media sites for updates and support and we would LOVE to hear from you – share what you and/or your students are creating!!

Check Us Out and Share Your Papers and Experiences:

  1. Classpad.net Youtube
  2. Twitter (@classpadnet)
  3. Facebook
  4. Our website – subscribe so you can start saving and sharing your work with others! Classpad.net

 

 

 

Stephen Hawking – Understanding the Universe

Pi Day is a day math and science enthusiasts love, not only for all the fun Pi Day activities, but also because it was Albert Einstein’s birthday, one of the most iconic mathematicians/scientists/physicists, who developed the theory of relativity. This year’s Pi Day, ironically, the world lost another renowned physicist, Stephen Hawking. Whether you never heard of Stephen Hawking until the movie The Theory of Everything (2014) or whether you only know him from his voice on the Simpsons or Star Trek, The Next Generation or The Big Bang Theory, his death is a loss to the world of science and math.

It seems silly for me to list all that Mr. Hawking contributed, when his website does such a terrific job of that already. Here is the link to his site, where you can read about Stephen Hawking, see the many publications of his, the books he wrote, the lectures he gave (transcripts), the movies about him and with him, and videos he made. This is a great resource for teachers and students to explore.

I want to leave you with a video of Stephen Hawking talking about his love of science and as he said “I did my work because I wanted to understand the universe”.

Rest in Peace and thank you for all your contributions that have helped the rest of us understand our universe a little better.

 

Applying Prior Knowledge Is About Precise Mathematical Language

In the course I am currently teaching at Drexel University, we have been focused on the importance of addition and multiplication properties as students progress through mathematics. Particularly the idea of inverse numbers (additive inverses and multiplicative inverses),the additive and multiplicative identities, and the commutative and associative properties of addition and multiplication. A strong foundation in these concepts, which starts in elementary school and builds as students progress to more abstract and complex math concepts such as proportional reasoning, solving equations, composition of functions, and working with matrices, is really important. In fact, if we spent more time using precise language and justifying our reasoning with properties consistently, as we model and help students learn and discover, there would be a lot less confusion and much more connection of prior knowledge to ‘new’ concepts. Instead, we often provide a short-cut, or a ‘trick’ (with a cute acronym like KSP (keep, switch, flip) or ‘Cross-multiply-divide’ with no basis in the true mathematics. Students focus on memorizing isolated rules versus connecting new concepts and seeing learning as just an extension of prior knowledge.

Let me try to explain what I mean by providing a sense of prior knowledge and how it connects to more abstract concepts:

Prior knowledge:

  • Additive identity: 0 and the Additive Identity Property:  a + 0 = a (5th/6th grade)
  • Additive inverses create the additive identity – so -b + b = 0 or -c + c = 0 (5th/6th grade)
  • Multiplicative identity: 1 and the Multiplicative Identity Property: b*1=b or 1*b=b (5th/6th grade)
  • Multiplicative inverses create the multiplicative identity (i.e. a 1) = d * 1/d = 1 or -1/f *-f = 1 (5th/6th grade)
  • Addition and multiplication are commutative (switch the order and you get the same solution) (1st/2nd grade) and associative (switch the grouping and you get the same solution) (3rd grade)(this explains why we want to change subtraction to addition of the additive inverse number, and why we change division to multiplication of the multiplicative inverse (reciprocal) – so we can USE THE PROPERTIES!!!

Understanding the above, then makes solving equations easier – and we don’t need to avoid equations with fractions or decimals, because the properties apply to these rational numbers as well.

Example:  -5 = (1/3) x – 8

  1. Change the problem to addition of the additive inverse: -5 = (1/3)x + (-8)
  2. Add 8 to both sides (commutative property – can add in any order) because adding additive inverses (8 and -8) make zero (additive identity property)  -5 + 8 = (1/3)x + (-8) + 8
  3.  Group the inverses (associative property) and solve:  -5 + 8 = (1/3)x + (-8 + 8) which is equivalent to 3 = (1/3)x + 0  equivalent to 3 = (1/3)x
  4. Use the multiplicative inverse property (multiplying by the reciprocal will create a 1) and multiply by 3/1 on both sides:  (3/1)*3 = (3/1) *(1/3)x (commutative property allows us to multiply in either order on both sides).
  5. The multiplicative identity property says 1 times any number is itself, so we end up with 9/1 = 1 *x or 9 = x

*Note – we did not use subtraction or division at all – we used the understanding of inverses, identities, and addition/multiplication properties to explain. No tricks, and working with actual numbers (so fractions and integers) with justification for all steps.

Example: Solve the proportion  3/16 = x/20

  1. This is really an equation where the quantity x is being multiplied by 1/20. Understanding that I can use the multiplicative inverse to multiply by the reciprocal to make a 1, I multiply both sides by 20/1:
    • 20/1 * 11/12 = x/20 * 20/1 (commutative property lets me multiply in either order on both sides)
    • I can even decompose my multiplication and think about making ones through the same understanding: 4*5*3 /4*4= 1*x
    • 15/4 = x/1 or x = 3.75 (multiplicative identity)
  2. Note – the trick we often tell students to memorize is ‘cross-multiply and divide’, but if instead we focused on just applying their understanding of multiplicative inverse and making those 1 pairs, there would be less confusion, less forgetting the ‘trick’, and less applying that trick to other problems where it is in appropriate. 

Obviously I can’t demonstrate a whole course of study in one blog post – what I am really emphasizing here is how important consistent mathematical vocabulary and use of properties is, instead of acronyms, short-cuts, tricks, mnemonics, etc. that we often give students with no basis in understanding. Instead of seeing math as a connected whole, building on to prior knowledge as they move through the grades and topics, we treat it as isolated topics with no connection. It’s no wonder students think every year they are learning something new. If last year when they worked with division of fractions their teacher taught them to “Keep, Change, Flip”, and this year the teacher is talking about Ketchup Covers Fries or KSF….no wonder they are confused. None of these are grounded in the properties and vocabulary of mathematics.

What we should be doing instead is focus on applying properties and using the mathematical language/vocabulary/properties right from the very beginning and ALL THE TIME. So instead of disconnected acronyms of KSF or KCF,  they focus on extending their understanding of additive inverse, inverse operations with the inverse number and division of fractions ends up being just an extension of what they did with subtraction of integers – i.e. use your inverse operation with the inverse number. So dividing with rational numbers is just multiplication (inverse operation) by the multiplicative inverse (i.e. reciprocal), similar to subtraction being addition (inverse operations) with the additive inverse (opposite signed number) – same general idea, same vocabulary, and just building on prior knowledge.

Let’s stop dumbing down mathematics and use the words and properties that truly allow students to connect and look for those patterns and develop their own understandings and rules. Let’s get away from tricks and mnemonics as our ‘teaching’ method – instead, let students figure that out themselves through the use of precise math language and application of properties. Let’s start in elementary school. Use precise mathematical language (along with clarifying words of course, but always with (not instead of) proper mathematical language/vocabulary/properties).

Think about it – we wouldn’t change the Spanish word for grandmother (abuela) or the French word for bread (pain) to other words, because then how would we communicate and be understood by others speaking those languages? Why is it okay to change the words or use different words or tricks, instead of the using the math language and properties? No wonder students are often so confused or why teachers think they have to ‘reteach’ things every year – if we are not consistent with students in using mathematical language, we are in fact talking a different language to them. No wonder they so often seem lost and frustrated.

Casio Scientific Calculator QR Code – The Power of Visualization

I was recently asked on my YouTube video channel if Casio’s graphing calculators also have QR code capabilities like the Casio FX991 ClassWiz Scientific Calculator. It was a great question – and my response was the graphing calculators don’t need that QR code because they already have the power of visualization. The purpose of a QR (Quick Response) code is to get information quickly, whether that’s an audio or a visual or data (usually on your mobile device). With graphing calculators, that is part of the calculator – we can enter data in many forms and see multiple representations of that data very quickly – a graph, a table, a function, specific points, etc.within the graphing calculator itself, making a QR code unnecessary. And, if you are using the graphing software/emulators, you can put these graphs and multiple representations up very quickly.

Why does the Classwiz then have a QR code? This is a scientific calculator, which is incredibly inexpensive (from $15-19), so what’s the reasoning behind including QR code capabilities? The answer – to add the power of visualization and make this calculator have ‘graphing’ capabilities at a fraction of the cost. You can enter data in the form of functions, tables, spreadsheets, and then have the ability to see graphical representations of this data with the QR code.

Here’s a short video that talks about the differences in the graphing calculator versus the scientific calculator and demonstrates the QR code. You will also see a comparison of the tables and graphs represented on both calculators.

Creativity of Students – Provide Opportunities for Expression

I was straightening up my office – something I realized I do not do enough. I found a file of student projects from when I was teaching Geometry over 15 years ago. We had done some geometry poems for Valentines day – i.e. write a poem that utilizes mathematics vocabulary (getting that ELA and creativity flowing in my students), and I had clearly saved a few of my favorites.  There were other files of student projects – scale drawings of bedrooms and furniture (so students could ‘rearrange’ their rooms using a scale model), dilation pictures, transformation sketches from Sketchpad, problem-solving portfolios, and designing an aerial view of a city using geometric shapes and properties. As I walked through memory lane, looking at student work from years ago and remembering specific students, it really made me miss those classroom experiences. And what I had forgotten is how incredibly creative and thoughtful students are when given the chance to express themselves – you learn so much about them if you let them, what they know about mathematics, what they think, and what they don’t know if you provide opportunities to approach mathematics creatively.

I’d completely forgotten about the problem-solving portfolios I did with both middle and high school students in all my courses. They were given a choice of problems connected in some way to the math content we were learning or applications of prior knowledge, etc., and they were to choose from several. They had to complete one per unit and put it in their portfolio as examples of their problem-solving and learning/application of mathematics. This was way before the ‘Common Core’, but as I look at my expectations, it was very Common Core like. The idea behind was really very much centered around helping students to persevere and think critically about problems, use problem-solving strategies, and explain their interpretation of a problem, plan out a solution path, justifying their thinking, and showing multiple ways to approach a problem, and analyze their solutions to see if they made sense.  Here are the ‘steps’ they needed to go through and demonstrate in their problem-solving:

  1. Restate the problem in your own words, writing out any questions or wondering you have about the problem.
  2. Create a solution plan – what do you think about the problem  and why (is it hard, easy, does it seem similar to something you have seen or done before), what math might be needed, what problem-solving approach will you start with and why do you think this might be a good approach? What do you think might be the solution, before you begin?
  3. Work through the problem – include everything, especially if you changed your original plan and why. Write down everything that comes to mind and what you did to think through things.
  4. What is your solution and why do you think this is a reasonable solution?
  5. Analysis of your problem solving – What did you think of the problem after working through it? What did you learn from doing the problem, either about yourself or about math, or both!?

In reading through some of these (I’ve posted some samples below from several different portfolios), you can ‘hear’ students personalities coming out, you can immediately see if they might have a misconception about what the problem is asking or an interesting approach to a solution, or identify those who really needed some extra support because their art work was more substantial then their mathematical work! It gives great insight into who might need some extra support or who might warrant some extra challenges. But mostly – the freedom to choose, think on their own and be creative and work through their problems provided students and ability to express their learning in a different way than an answer on a test. I remember at the time I was considered a rather eccentric MS/HS teacher because I did all these ‘strange’ things like keep math portfolios and journals, use manipulatives, used technology (Sketchpad) and projects instead of tests to demonstrate learning. But – in looking back on the past, and looking at what we want from students today in mathematics, with College and Career Ready Standards and Mathematical Practices, I think it’s the right path. Provide students opportunities to think, choose, be creative, find multiple solutions, justify their answers and question their results. It brings out their creativity and they learn to express themselves as mathematicians.

 

Geometry and the Holidays

The holidays are upon us, so of course it makes complete sense to look for geometrical connections. Or maybe that’s just me?

As a geometry teacher (just finishing up a Geometry & Spatial Reasoning course), I am seeing geometry connections everywhere. From the wrapped presents, to the origami ornaments, to the snowflake patterns, I am constantly looking for those real-world connections and easy (and cheap), ways to get students working hands-on with math.

We are all familiar with ‘holiday math’ problems that connect to wrapping presents – i.e. how much wrapping paper do you need, how much ribbon, etc. Area, surface area, linear length connections all very obvious. But, as a geometry teacher, I am also curious about the gift boxes themselves. I know it is often difficult to find 3D models for learning, so boxes provide a cheap way to provide students hands-on explorations of nets, area, surface area, volume. So – teachers – get your students to bring in boxes after the holidays – so much you can do with these!!

Another thought – origami. This time of year, teachers often create holiday decorations with their students with paper-folding, which is fun, obviously, but can also be a great way to apply many math concepts. Shapes, fractions, and transformations for example. Take the following two origami designs – a star and a tree. As you are folding, you could be having students think about the individual shapes, but also the dimensions, the fractional parts after making a fold, what types of transformation have occurred – even congruence and corresponding parts.

money-origami-star-finishedIstep-step-instructions-how-to-make-origami-star-toy-cartoon-cute-paper-steps-84628139

For example, in the star above, after folds #1, what fraction of the square does each smaller square represent? When we fold that triangle in #2, what type of triangle is it? What fraction of the original square is represented in that yellow triangle?  What type of transformation does each fold represent? Are the triangles in #3 and #4 congruent? How do you know?

images (1)step-step-instructions-how-to-make-origami-christmas-tree-illustration-67138886

Again, looking at the tree folding above, what shapes do you see in #1? What fraction of the whole paper is each shape (so squares and triangles)? How about in #2? And which shapes are congruent? How do you know? Lots of great math, that you could really explore with students while they are also doing a fun hands-on activity.

Hopefully you can use some of these ideas with your students. Have a wonderful holiday season!!