Showing posts with label Mathematics. Show all posts
Showing posts with label Mathematics. Show all posts

Wednesday, 12 November 2014

What is Wrong with an Algorithm?

Nothing! Yes I said nothing! Let me elaborate.

In conversation today I was asked, "What is wrong with an algorithm?"  I get this question a lot. Now this question was asked because like us all we were taught to do an algorithm so we always do what is familiar for us. The question also came about because they were afraid of teaching their child the wrong way.

This inspired me to write this blog post. There is nothing wrong with learning an algorithm; there are some risks in only learning this but there is nothing wrong.

An algorithm was first invented in order to make math easier to do. We have to remember that calculators were not invented at this time and may people were using abacuses and basically counting by ones or a base 16 system. With the use of an algorithm counting became procedural and easier to do.  However, those using it understood mathematical foundations of why the algorithm worked.

This is the problem with introducing the algorithm to early. Let's just reflect on our own understanding of basic addition. We honestly did not learn how to add by using an algorithm first and to be fair our first insistence of remembering an algorithm (at least in my guess) was probably around grade three maybe four. This means that for four-five years, depending if you were in the pre-school or JK error you had a lot of experimentation and exploring in counting, saying numbers, ordering numbers and subitizing.  The problem is that we often forget all of the steps it took us in learning an algorithm.

For the past ten years I have been looking closely at how students learn mathematics. One of the foundation research pieces have been Fosnot and Dolk's landscape of Learning (2000). (full file)



I know that the picture is small but you can see all of the learning that a student has to go through in order to get to an understanding of algorithms.

Now here is my problem with starting with algorithms to early:

1) It doesn't teach proper number sense:

Now you may question me on this but in my honest opinion it doesn't teach proper number sense. The problem is that when a person does an algorithm it forces you to only look at numbers from 1-9. There is no true understanding of our base ten system. Students do not really understand why or how 1 group of ten can be ten things yet 1 ten. This is often seen when you ask a student tell you the value of a two digit number (let's say 24). When you point to the ten's column they will say the value is two. They will even go as far as counting 24 objects then pulling two of them to signify the value. This can also be seen when students use base ten blocks and they count the rods as two instead of twenty.

2) Basic procedural errors:


Now these errors may be dismissed as, they just have to learn the proper procedure. However, these are troubling errors because students not only are procedurally doing the operations wrong they are also struggling with reason-ability of answers or what I like to call no number sense.  

What I propose instead:

In my math class we work hard on developing a number line.  Learning this strategy does a lot of things: 

1) It allows all students to grasp a strategy whether they are counters by one or able to skip count proficiently. 

2) It teachers all of the rudimentary learning of number sense. Students learn one to one tagging, cardinality, subitizing, magnitude and many more options all in one strategy.

3) Eventually they develop more proficient mental strategies because they can conceptually understand what is happening to the numbers.

4) There is no need to regroup and or borrow with a number line, just the use of number sense.  I find this to be the biggest problem with algorithms. For example, let's take 56-49=7. Now for many of us we may not need to use an algorithm but ask your child or a younger student they will start by borrowing from the 5 (not fifty) to make 16 because you cannot take 6 from 9 (which we also no is not true-- ask anyone in debt or who has a mortgage) and then they will realize the answer is five. However, if students are taught proper number sense, they realize that they can just count up to the answer.

A number line also develops efficient mental math strategies that are far faster then whipping out a piece of paper and borrowing or regrouping.  Take a look at some of my grade twos thinking (all done 


By allowing my students to explore, question and develop their number sense they are better mathematicians and yes we have discussed an algorithm, we have developed an understanding of how to use it but my students make less mistakes with a number line then with an algorithm. And to be honest they much prefer the number line then the algorithm, most of the time they do this because that is what they think they need to do.

One of the biggest problems in our math programs today is that we often jump to far into the abstract without thinking about the concrete work that people need to develop in order to understand these concepts.

What do you think? When and where should algorithms be taught? How do you develop number sense? Love to hear your thoughts.

For further reading I recommend reading:

1) Fosnot, C. T., & Dolk, M. L. A. M. (2001). Young mathematicians at work. Portsmouth, NH: Heinemann.

2) Anghileri, J., Beishuizen, M., & Van Putten, K. (2002). From informal strategies to structured procedures: mind the gap!. Educational Studies in Mathematics,49(2), 149-170. 

3) Kami and Dominck: The Harmful effects of Algorithms in 4-9

Thursday, 16 January 2014

Why teach through inquiry? A real testimonial


Now I know that I have posted on this subject before but with the day I had I just had to write about it again.  Inquiry: WOW!  Man I love it.

I know that recently there has been a lot of discussion about inquiry in the classroom and if it is really making students learn.  There has also been a huge push to go "back to basics" all I have to say is wish you were in my class (even school) today.  Today's math problem was quite simple: 

"Mrs. Standring, our proud principal, needs help.  Our school has been open for two years now and we got more kids this year, because of that the fire Marshal has asked her to make a new fire plan.  I was telling her that we were studying measurement and she thought you could help.  How far is our door to the nearest fire door?"

The kids went nuts. It took them a while to get over the fact that they were helping Mrs.Standring.  Well they just started with the questions: what tools can we use? How are we starting? Which door is closer?

Most of them saw that a meter stick would be the best measurement tool, we had been talking about measurements for some time and been measuring in non-standard too and knew that it was inconsistent. So they all grabbed meter sticks and off they went.


We got a bunch of numbers and came to the carpet to discuss. They were all in confusion, why do we have different numbers. We used a standard measurement? We then asked the students to demonstrate how they measured.  Some saw that when you lift the ruler up, you sometimes, overlap the space or leave a gap.  I then asked them how can we prevent that?  This brought up the discussion of leaving marks, or placing fingers.  They went back at it.


Students then came up with an answer but when I asked them to tell our principal they didn't know what to say.  This of course then led us into a discussion about explanation texts, which we then made some success criteria and off they went to write.  When the bell rang half way through the students were very upset that they didn't have enough time to finish there work.

Not only did this problem happen in my classroom but my teaching partner did it too.  Her kids thought string was the best and then bring it back to measure against a meter stick.

Now you may read this and say so what? So what! The best part of this is that all this discussion was student driven. All collaboration, student driven, all learning student driven.  Yes as a teacher I am incharge.  I have planned this problem, I have thought of the big ideas and questions but it is the passion, and learning of my students that drive this problem.  Also, when looking back (though I will say to make it worth while this should be done first) my students met over 37 expectations from the curriculum and all of the learning skills that are in the report card.  In addition, the talk was amazing and the learning even more. Not only this but when it comes to assessment I have it all, with no tests.  I know my students skills, next steps and a mark of work.

Inquiry for me is the only way to teach.  Yes, students do need facts and knowledge but that fact and knowledge is gained through the inquiry process.  Also, if a student doesn't have that to start with as a teacher it is my job to scaffold the question so that they do learn; however, it should still be done in a way that the student is discovering the learning.

Now in the end, there is no wrong way to teach, all learning is valid and good. But through inquiry students do grasb and understand concepts faster and with a deeper understanding. It's been amazing to see our students development as our school adopts this approach. There is less review needed from year to year and the students are talking more and communicating their thoughts.  For me there are a couple of key reasons to teach through inquiry:

1) Students learn and enjoy the lessons more then traditional teaching styles

2) It covers more curriculum and deeper knowledge

3) Students retain information

4) Learning is integrated in real life, why separate at school

5) It validates the students and makes them buy into their learning. If they are invested you have less behaviours

6) students easily tune a teachers voice out but not their peers

7) It's fun for me too! Shh don't tell my students

What are some potential problems: (though to me they are not problems)

1) Problems take time: learning is not easily divided into 30, 40 minute time blocks

2) Can be and should be noisy but productive

3) Takes more planning: yes it takes more planning. You cannot wing inquiry. Even though it may appear as if it is winged or that the teacher is doing nothing it is an art form and requires a lot more planning (will tough on that in a minute)

4) Parents: you will get parents complaining and questioning your practice.  This is new for many and with new comes questions and fears. Stand up and proudly defend your practice because when they hear and see their kids they will love you.

5) you may not have all of the answers

What do I need to do to teach through inquiry?

1) know your content and curriculum: when you know your students learning it is easier to formulate questions and scaffold students learning.

2) plan: I wrote a previous blog post about planning but essentially you need to plan.  Inquiry does not happen by the seat of your pants.  You need to anticipate students questions, problems, and ideas.  You need to know what the big ideas are and where you want the lesson to go.  You need to understand learning trajectories and see where your class is and should go next and you need to do the problem first.

3) inquiry should be contextual and related to the kids life.  The best inquiries are ones in which the students really wonder or can invest in.

4) have fun and don't be afraid to make a mistake.


Overall, I feel inquiry has been one of the best things I could have done. It really benefits the students and it makes my assessment easier.  I would love to hear your thoughts on inquiry? Have you tried it? Struggles? Pointers? Thanks for reading.



Wednesday, 30 October 2013

Accountable Talk in the Classroom: Practical Advice for the Classroom

I have recently finished one great book and one great article on Accountable Talk and Classroom Discussions. 


Stein, M. K., Engle, R., Smith, M. & Hughes, E,  Orchestrating productive mathematical discussion: Five practices for  helping teachers move beyond show and tell. Mathematical Thinking and Learning, 10313-340. 


Chapin, Suzanne, O'Connor, Catherine, & Anderson, Nancy. Classroom Discussions: Using         math talk to help students learn. California: Scholastics. 2009.


Accountable talk is one of my passions as I have spent the last four year studying the impact it has on my classroom.  I highly reccomend these two readings for anyone interested in learning more about accountable talk.  However, I also know that in teaching we really don't have time to sit down and read.  For this reason I thought I would summarize them for you and include them in my blog (I appologize in advance as this will create a rather long post).  These ideas come from the two resources above and my own thesis work.  I hope they are practical advice for anyone in their teaching practice.


Implementing Classroom Discussions
Establishing and Maintaining a Respectful, Supportive Environment:
·         LAY DOWN THE LAW (in a collaborative manner):
o   that every student is listening to what others say
o   that every student can hear what others say
o   that every student may participate by speaking out at some point
o   all have an obligation to listen
·         neither student or teacher will participate in bad environment.  Everyone needs to feel comfortable.
·         Emphasize the positive and forestall the negative
·         Establish classroom norms around talk, partner work, and discussions (what does it look like, sound like and what should we be doing)
·         everyone has the right to participate and an obligation to listen
Focusing Talk on the Mathematics:
·         During the discussion time you need to focus the talk on math:
o   plan your questions carefully
o   Have good formative assessment happening at all times
o   Make a plan as to what big ideas you want to cover
o   Anticipate problems and possible solutions
Providing for Equitable Participation in the Classroom Talk:
·         Here are some strategies that will assist you in making it all equitable:
o   Think-pair-share
o   Wait time
o   Group Talk
o   Partner Talk
o   Debates
o   Random  Choice on who Talks

 
Types of Talk Moves:
Talk Moves That Help Students Clarify and Share Their Own Thoughts
·         Say More:
o   Here you literally ask the student to explain more.  "Can you tell me more?", "Tell us more about your thinking.  Can you expand on that?"; or "Can you give us an example?"
o   This sends the message that the teacher wants to understand the students' thinking.
·         Revoicing:
o   It is sometimes hard for students to clearly articulate what they are trying to say by revoicing or having a student do this it allows the original student to check and make sure what they said is true or to hear it in a new way
o   It is not just repeating but more of paraphrasing the students ideas
·         Model students thinking:
o   This is not so much a talk move as it is a way to help talk
o   As students talk record what they are saying without comment.  When they are done ask them , is this what you meant?
o   This allows students to reflect and think about what they said in comparison to what was written
·         Wait Time:
o   Wait time is so important.  I cannot stress this enough.  The longer you wait the better responses you will get.  It allows students to process what you or another student asked and be able to formulate their thinking
Talk Moves That Help Students Orient to Others' Thinking
·         Who can Repeat?
o   I would classify this under the first category but it also helps students with understanding what their peers are saying
Talk Moves that Help Students Deepen Their Reasoning
·         Press for reasoning
o   Here you are basically asking students to think about why they did this.  This can be done by asking:
§  Why do you think that?
§  What convinced you that was the answer?
§  Why did you think that strategy would work?
§  Where in the text is their support for that claim?
§  What is your evidence?
§  What makes you think that?
§  How did you get that answer?
§  Can you prove that to us?
o   Not only are these excellent talk moves but excellent questions that push students beyond their thinking and make excellent mathematical connections.

Talk Moves That Help Students Engage with Others' Thinking
·         These are excellent questions that help students build upon their own thinking and the thinking of the community
·         Do you agree or disagree...and why?
o   This really brings students into direct contact with the reasoning of their peers
o   You can do this by:
§  Thumbs up or thumbs down
§  Why do you agree or disagree?
·         Who can add on?
o   When you ask this question make sure that you wait for answers as this may need time to develop connections.


1: Anticipation (P.322)
The first thing is for the teacher to look and see how students might mathematically solve these types of problems.  In addition, teachers should also solve them for themselves.  Anticipating students’ work involves not only what students may do, but what they may not do.  Teachers must be prepared for incorrect responses as well.
2: Monitoring students' work (P. 326)
While the students are working, it is the responsibility of the teacher to pay close attention to the mathematical thinking that is happening in the classroom.  The goal of monitoring is to identify the mathematical potential of particular strategies and figure out what big ideas are happening in the classroom.  As the teacher is monitoring the students work, they are also selecting who is to present based on the observations that are unfolding in the classroom.
3: Selecting student work (P.327-328)
            Having monitored the students, it is now the role of the teacher to pick strategies that will benefit the class as a whole.  This process is not any different than what most teachers do; however, the emphasis is not on the sharing, but on what the mathematics is that is happening in the strategies that were chosen. 
4: Purposefully sequencing them in discussion (P. 329)
With  the students chosen, it is now up to the teacher to pick the sequence in which the students will present.  What big ideas are unfolding, and how can you sequence them for all to understand?  This sequencing can happen in a couple of ways: 1) most common strategy, 2) stage 1 of a big idea towards a more complex version or 3) contrasting ideas and strategies.
5: Helping students make mathematical sense (P.330-331)
As the students share their strategies, it is the role of the teacher to question and help  them draw connections between the mathematical processes and ideas that are reflected in those strategies.  Stein et. al. suggest that teachers can help students make judgments about the consequences of different approaches. They can also help students see how the strategies are the same even if they are represented differently.  Overall, it is the role of the teacher to bridge the gap between presentations so that students do not see them as separate strategies, but rather as working towards a common understanding or goal of the teacher.
 


Trouble Shooting Talk in the Classroom

My Students won’t Talk:

v  First ask yourself: our my students silent because they have not understood a particular question? --> sometimes they need to hear the question a few times and have time to think
§  if this is the case then give students time to think  (wait time is very important)
§  also revoice it or have another student revoice the question
v  Second they may be shy or unsure of their abilities:
§  If this is the case you may need to revisit strategies for talking
§  Think-pair-share is an excellent way to get kids comfortable to talk
§  it will also take time to get kids comfortable.  Wait time again is important as it holds students accountable.  Also making them feel comfortable and that mistakes are okay will assist with this difficulties

The same few students do all the talking:

v  Wait-Time:
§  I know that I say this a lot but it allows the other students to think and then participate while making the ones who always participate  (it will feel awkward at first but wait as long as you can)
v  Have students Revoice:
§  This is good strategy to bring validity to students answers and encourage others to talk
v  Conferencing with the ones who talk a lot:
§  You also don't want to ignore the ones who talk  all the time.  You can talk to them and let them know that you are not ignoring them but are just trying to allow others to participate.
v  Turn-Taking/ Random presenters/ group discussions:
§  These are all roughly the same strategy.  It allows you to have certain presenters share their thinking without offending or allowing others to take over the conversation

Should I call on students who do not raise their hands?

v  there is research to suggest that students will learn by listening but you will also hinder the class progress in discussion.  To help try creating a positive space that allows all students to feel comfortable and willing to participate.
v  "right to pass": 
§  allow students at the beginning of the year the right to pass.  You'll notice that they may do this at first but as you build the community they do this less and less
v  Call on reluctant to students after partner talk:
§  Often when you give them a chance to share first they are more willing to share or at least have a response from their partner

My students will talk, but they won’t listen

v  Set the classroom Norms:
§  remind each students that they have the right to be heard but that this also means an obligation to listen
v  Students Revoice:
§  When students need to revoice then they have to listen

Huh?” How do I respond to incomprehensible contributions?

v  The temptation is to simply say, "Oh, I see.  How interesting...." and quickly move on to another student.
v  Try Revoicing or repeating what they have said.  After you have done this ask them is this what you meant?
v  Record their strategy on the board and ask them is this what you meant?

Brilliant, but did anyone understand?

v  Repeat what they said, then have another student repeat what they have said (if really important have many students repeat)
v  Break the explanation up into small chunks and revoice or have the students

I have students at very different levels

v  Pair students in ability groups:
§   Similar abilities with similar abilities.  This allows students to contribute at their level and to also struggle at their level.  In addition, it allows you as the teacher to differentiate as needed.  When you scaffold you can do so by group not by individuals
v  Parallel Tasks:
§  Give students similar tasks but with varying degrees of difficulty (still around the same big idea)

What should I do when students are wrong?

v  First ask yourself is there anything wrong with having the wrong answer?  Sometimes wrong answers provide rich and meaningful discussions
v  Need to establish Norms around respectful discourse and discussion with wrong answers
v  Mistakes are always an opportunity for learning to happen



This discussion is not going anywhere or Students’ answers are so superficial!

v  This may be happening because you are asking to many students to share or revoice the ideas that are happening in the classroom or in the case of superficial classroom  norms have not been established or the types of questions have been simple and direct
v  Use the working on phase as an opportunity to direct your bigger discussion:
§  As you are walking around and looking at work, look for the progression your students are taking.  This will lead you to a group discussions.  What questions are the students asking themselves?  What problems are occurring?  What big ideas are they trying to work out, have worked out or are struggling with?
v  Look at the type of questions that you are asking:
§  As teachers we are comfortable asking questions but do our questions already have responses?  Are we leading the kids to OUR thinking or our we allowing the students talk to LEAD the thinking.  Yes you are very much in control of the discuss and have to lead but it is not YOUR thinking but THEIRS that should be articulated.
§  Higher order questions build-upon or go beyond the thinking that is being presented.  As a teacher we need to help with the connections in mathematics.  Compare student work?  Compare strategies, Pros and Cons, naming and identifying.  We need to go beyond just show and tell