Hi Bill --
I think the main thing in teaching "number" is to distinguish it from "name" or "numeral" -- and I think the rush towards teaching "base 10 numerals" too early is one of the big problems in early elementary mathematics. Numbers are ordered ideas that can be put in correspondence and taken apart and recombined at will. Names and numerals are symbols for these ideas that have varying degrees of usefulness for different purposes. So one of the biggest questions any math educator should ask is: what symbols should I initially employ for numbers to help children understand "number" most throughly?
Most "child math" experts - like Mary Laycock, Julia Nishijima, etc. - would argue that a wide variety of analog (both unary and continuous) representations should be employed together (bundles of sticks, bags of objects, lengths of stuff, etc.), and each of these can have several labels attached ("one", 1, etc.). These can stay in use for much longer than is usually done in school. E.g. Some really great "adding slide rules" can be made from rulers, and then the children can make some really detailed large ones (even using their playground for baselines). These adding slide rules can add any two numbers together very accurately, whether "fractional" or not, and they can have scale changes to reveal what is invariant about two numbers (their ratio), etc. This can be used to make multiplication machines, etc.
Another use of number that uses names in a non-destructive way is the "equality game" of "how many ways can you make a number". First graders are very good at this an even though they don't know what "1000000" stands for (except it is large) they understand that they can make this or any other number many ways by a combination of additions and subtractions that add up to zero. This is a way to start algebraic thinking without needing variables. And so forth.
Wu actually makes a point against himself when he argues that phonics decoding is a good idea, even though no fluent reader decodes. This is similar to how sight reading is taught, especially for keyboards. Eventually the pattern results in a direct hand shape and mental "image" of the sound (or for text reading, a mental image of the idea). The question is how to get there, and teaching how to decode seems to help a little in early stages (maybe even just for morale purposes) rather than trying to teach either like Chinese characters. It takes 2-5 years to get fluent at such learning, so there usually need to be other supporting mechanisms (not the least is material that can be dealt with successfully after a few months or a year).
So, what Wu should be asking is "what framework do children need to get started in number and mathematical thinking about number?".
Another interesting example of what is not happening came out in a Mary Laycock workshop in which I was a "floor guy" (literally since I was on the floor with the children). One of Mary's games was to hand out a series of sheets of 10 by 10 squares, each divided in regions, with the question, "how many squares are in each region?" The 4th-5th grade children start by counting the squares in the regions. As the regions got more complicated, the children did not see that they could switch over to geometrical reasoning -- to see what fraction of the whole was occupied by each region and then divide -- instead they kept on trying to count the little squares and fractions of squares. Children who had learned to think mathematically would have had a strategy to look for the best representations for the problems, and these children had not acquired many (if any) math meta-skills.
To bring up a musical analogy again ... one of the best collections of advice about how to teach children to play the keyboard is in Francois Couperin's 1720 treatise "The Art of Playing the Harpsichord". First, he says, keep the children away from the harpsichord because it isn't musically expressive enough. And keep away from sheet music because it "isn't music". Instead, take them to the clavichord (loud, soft, and pitch modulation -- more expressive than a piano) and teach them how to play some of their favorite songs that they like to sing, and help them be as expressive in their playing as their singing is. This is music. Play duets with the children, etc. After they have done this for a sufficient time (from 6 months to several years), then you can introduce them to the initially less expressive harpsichord (which, like the organ, can only be expressive through phrasing). But they will have learned to phrase very naturally from their clavichord experience and this will start to come out in their harpsichord playing. Finally, now that they have learned to "talk" (my metaphor), they can learn to read. Now they can be shown the written down forms of what they have been playing. And now they can start to learn to sight read music.
When I was teaching guitar long ago, I used this basic scheme as much as possible, because "real guitar" has to be both music and "attention out" (so that you can mesh musically in a conversation with other musicians). Also, the guitar has some serious physical problems which have to be addressed gradually over weeks and months. Getting the students to play real stuff while all this is going on makes a foundation for the next level of much harder work. Learning to play patterns by ear allows the player to concentrate on their musicality and accuracy. Then they can be shown the patterns as both shapes and as decoded mappings in members of a key, etc.
The egregiously misunderstood Suzuki violin method also follows these ideas. (It isn't mechanical -- read his books.)
Couperin's essay is a pretty good set of distinctions concerning the general confusions between art and technique, and between ideas and media. You eventually have to get to all of these, but leading with art and ideas tends to preserve art and ideas, and leading with technique and media tends to kill art and ideas. I think it is really that simple.
Cheers,
Alan
At 03:47 AM 11/25/2007, Bill Kerr wrote:
Good discussion :-)
To be honest I've never been certain about the best way to teach "number" and have tended to try a smorgasboard in practice
Perhaps Alan is correct David?
Professor Wu (good mathematician) is making a brave attempt to make the teaching of algorithms to young children more concrete but his approach still puts too many demands on most children. From my experience of teaching of maths I feel that for disadvantaged students too many eyes would glaze over for some of the steps. It might work for his children but not for 90% of children.
I still feel that he makes some valid points and criticisms. I like the transparency and open-ness of his paper, as well as the conceptual position put by its title.
Another paper by Ellerton and Clements identifies the main issue as this: "... many children who correctly answered pencil-and-paper fraction questions such as 5/11 x 792 = q could not pour out one-third of a glass of water, and of those who could, only a small proportion had any idea of what fraction of the original full glass of the original full glass of water remained"
- Fractions: A Weeping Sore in Mathematics Education
http://www.aare.edu.au/92pap/ellen92208.txthttp://www.aare.edu.au/92pap/ellen92208.txt
Some form of effective kitchen maths needs to come before algorithms.
At this stage I'm left with more questions than answers.
-- Bill Kerr http://billkerr2.blogspot.com/http://billkerr2.blogspot.com/
On Nov 25, 2007 3:28 AM, Alan Kay <mailto:alan.kay@vpri.orgalan.kay@vpri.org> wrote: Hi Bill --
I just read Professor Wu's paper. I agree in the large with his assertion that the dichotomy is bogus, but I worry a lot about his arguments, assumptions and examples. There are some close analogies here to some of the mistakes that professional musicians make when they try to teach beginners -- for example, what can a beginner handle, and especially, how does a young beginner think?
Young children are very good at learning individual operations, but they are not well set up for chains of reasoning/operations. Take a look at the chains of reasoning that Wu thinks 4th and 5th graders should be able to do.
Another thing that stands out (that Wu as a mathematician is very well aware of at some level) is that while people of all ages traditionally have problems with "invert and multiply", the actual tricky relationship for fractions is the multiplicative one a/b * c/d = (a * c)/(b * d) which in normal 2D notation, looks quite natural. However, it was one of the triumphs of Greek mathematics to puzzle this out (they thought about this a little differently: as comeasuration, which is perhaps a more interesting way to approach the problem).
A few years ago I did a bunch of iconic derivations for fractions and made Etoys that tried to lead (adults mostly) through the reasoning. One of the best things about the divide one is that it doesn't need the multiplication relationship but is able to go directly to the formula. So these could be used in the 5th grade.
But why?, when there are much deeper and more important relationships and thinking strategies that can be learned? What is the actual point of "official fractions" in 5th grade? There are many other ways to approach fractional thinking and computation. I like teaching math with understanding, and this particular topic at this time - and provided as a "law" that children have to memorize - seems really misplaced and wrong. Etc.
Cheers,
Alan
At 05:53 AM 11/24/2007, Bill Kerr wrote:
David:
Further, but perhaps drifting off topic for squeakland, is it provable that 'back to basics' and 'progressivism' are equally as inadequate?
Alan: I said above that the simplistic versions of both are quite wrongheaded in my opinion. If you don't understand mathematics, then it doesn't matter what your educational persuasion might be -- the odds are greatly in favor that it will be quite misinterpreted.
David,
I read the original maths history http://www.csun.edu/%7Evcmth00m/AHistory.htmlhttp://www.csun.edu/~vcmth00m/AHistory.html that prompted your initial questions about constructivism and agree that it critiques the cluster of overlapping outlooks that go under the names of progressivism / discovery learning / constructivism - fuzzy descriptors
But more importantly IMO it also takes the position that the dichotomy b/w "back to basics" and "conceptual understandings" is a bogus one. ie. that you need a solid foundation to build conceptual understandings. The problem here is that some people in the name of constructivism have argued that some basics are not accessible to children. (refer to the H Wu paper cited at the bottom of this post)
I think the issue is that real mathematicians who also understand children development ought to be the ones working out the curriculum guidelines. This would exclude those who understand children development in some other field but who are not real mathematicians and would also exclude those who understand maths deeply but not children development.
This has not been our experience in Australia. I cited a book in an earlier discussion by 2 outstanding maths educators documenting how their input into curriculum development was sidelined. National Curriculum Debacle by Clements and Ellerton http://squeakland.org/pipermail/squeakland/2007-August/003741.htmlhttp://squeakland.org/pipermail/squeakland/2007-August/003741.html For some reason the way curriculum is written excludes the people who would be able to write a good curriculum -> those with both subject and child development expertise
For me the key section of the history was this: "Sifting through the claims and counterclaims, journalists of the 1990s tended to portray the math wars as an extended disagreement between those who wanted basic skills versus those who favored conceptual understanding of mathematics. The parents and mathematicians who criticized the NCTM aligned curricula were portrayed as proponents of basic skills, while educational administrators, professors of education, and other defenders of these programs, were portrayed as proponents of conceptual understanding, and sometimes even "higher order thinking." This dichotomy is implausible. The parents leading the opposition to the NCTM Standards, as discussed below, had considerable expertise in mathematics, generally exceeding that of the education professionals. This was even more the case of the large number of mathematicians who criticized these programs. Among them were some of the world's most distinguished mathematicians, in some cases with mathematical capabilities near the very limits of human ability. By contrast, many of the education professionals who spoke of "conceptual understanding" lacked even a rudimentary knowledge of mathematics.
More fundamentally, the separation of conceptual understanding from basic skills in mathematics is misguided. It is not possible to teach conceptual understanding in mathematics without the supporting basic skills, and basic skills are weakened by a lack of understanding. The essential connection between basic skills and understanding of concepts in mathematics was perhaps most eloquently explained by U.C. Berkeley mathematician Hung-Hsi Wu in his paper, Basic Skills Versus Conceptual Understanding: A Bogus Dichotomy in Mathematics Education.75"
Papert is also critical of NCTM but is clearly both a good mathematician and someone who understands child development - and has put himself into the constructivist / constructionist group
I followed that link in the history to this paper which is a more direct and concrete critique of discovery learning taken too far, with well explained examples of different approaches:
http://www.aft.org/pubs-reports/american_educator/fall99/wu.pdfhttp://www.aft.org/pubs-reports/american_educator/fall99/wu.pdf
BASIC SKILLS VERSUS CONCEPTUAL UNDERSTANDING A Bogus Dichotomy in Mathematics Education BY H. WU
cheers,
Bill Kerr http://billkerr2.blogspot.com/http://billkerr2.blogspot.com/
On Monday 26 November 2007 8:03 pm, Alan Kay wrote:
... So one of the biggest questions any math educator should ask is: what symbols should I initially employ for numbers to help children understand "number" most throughly?
Coming from a culture steeped in oral tradition, I find 'sounds' better than 'symbols' when doing math 'in the head'. The way I learnt to handle numbers (thanks to my dad) is to think of them as a phrase. 324+648 would be sounded out like "three hundreds two tens and four and six hundreds and four tens and eight. three hundreds and six hundreds makes nine hundreds, two tens and four tens make six tens and four and eight makes one ten and two, giving me a total of nine hundreds seven tens and two". Subtraction was done using complements. So 93-25 would be sounded out as "five more to three tens, six tens more to nine tens and then three more, making a total of six tens and eight'. The technique works for any radix - 0x3c would be "three sixteens and twelve'.
In India, many illiterate shopkeepers and waiters in village restaurants use these techniques to total prices and hand out change. No written bills.
The advantage with sounds is that tones/stress/volume can be used to decorate numbers. With pencil and paper, changing colors, sizes or weights would be impractical.
Subbu
On Mon, Nov 26, 2007 at 11:38:30PM +0530, subbukk wrote:
On Monday 26 November 2007 8:03 pm, Alan Kay wrote:
... So one of the biggest questions any math educator should ask is: what symbols should I initially employ for numbers to help children understand "number" most throughly?
Coming from a culture steeped in oral tradition, I find 'sounds' better than 'symbols' when doing math 'in the head'. The way I learnt to handle numbers (thanks to my dad) is to think of them as a phrase. 324+648 would be sounded out like "three hundreds two tens and four and six hundreds and four tens and eight. three hundreds and six hundreds makes nine hundreds, two tens and four tens make six tens and four and eight makes one ten and two, giving me a total of nine hundreds seven tens and two". Subtraction was done using complements. So 93-25 would be sounded out as "five more to three tens, six tens more to nine tens and then three more, making a total of six tens and eight'. The technique works for any radix - 0x3c would be "three sixteens and twelve'.
In India, many illiterate shopkeepers and waiters in village restaurants use these techniques to total prices and hand out change. No written bills.
The advantage with sounds is that tones/stress/volume can be used to decorate numbers. With pencil and paper, changing colors, sizes or weights would be impractical.
Subbu,
Thanks for sharing this. I think that it is very interesting that sound and oral skills can be a basis for mathematical thinking. My cultural background is less oral, so I did not even think of this as a possibility. It seems that music and mathematics are somehow connected, but I never thought to extend this to verbal types of music.
Dave
On Nov 26, subbukk wrote:
So 93-25 would be sounded out as "five more to three tens, six tens more to nine tens and then three more, making a total of six tens and eight'. The technique works for any radix - 0x3c would be "three sixteens and twelve'.
I imagine this would work very well for systems with multiple bases, like pounds-shillings-pence, days-hours-minutes-seconds. Does it?
My mental model for arithmetic is a clock face, which is very clumsy in base 10 (and worse in base 16!)
Thanks for sharing this subbuk
Best, David
From: David Corking
My mental model for arithmetic is a clock face, which is very clumsy in base 10 (and worse in base 16!)
Hi David,
This is very interesting. Something I had not thought of, but it makes perfect sense that a picture of numbers would help. I found something very similar playing Sudoku. It's a lot of fun. When I first started playing I would find missing numbers by counting from 1 to 9 and looking for the missing numbers. It became obvious to me that I didn't need to do that and that I could just look at all the numbers at once and for what ever reason the picture itself allowed me to figure out what was missing. The mind works in very amazing ways!
Ron
Ron Teitelbaum wrote:
My mental model for arithmetic is a clock face, which is very clumsy in base 10 (and worse in base 16!)
This is very interesting. Something I had not thought of, but it makes perfect sense that a picture of numbers would help.
My clock face model is clumsy and prone to errors (except when calculating times which is fine). However it seems more useful than memorising relationships between numerals, which I think some people do.
I didn't purposely invent my clock face model or consciously try to adopt it. Unfortunately It just emerged in my head in the first year or two of elementary school and dominates my thinking about number. I suspect a more tactile and flexible model, like an abacus or cuisenaire rods, would have made mental arithmetic much easier. Perhaps it could have made the beautiful structures in numbers more accessible to me, such as primes, the fibonacci sequence, irrationality, perfect numbers, fractals and so on. Anyway - sexagesimal arithmetic is trivial for me. And I love hearing about others' internal models.
Meanwhile I still remember reciting multiplication tables out loud, and those facts (reinforced by auditory and oral/verbal memory) are also invaluable tools for my mental arithmetic. Whether they help me to think mathematically is a different question which I don't think I am able to address. This experience suggests to me that while neither numerals nor the names of numbers seem to be very useful in grasping the basics of number, they become useful later for acquiring facts that lead to other skills and areas of understanding.
Etoys uses numerals a lot (in tiles and watchers) but also uses some other very compelling representations of number, such as polar coordinate vectors, sound and movement. It would be interesting to add more representations to Etoys, such as tally charts, rods, an abacus, tesselating shapes, liquids: to see if they help children become fluent in logarithms, polynomials, statistics, complex numbers and other things that bring back bad high school memories for my generation (or indeed fun and enlightening math things that are not traditional school math, like fluid mechanics, statistical mechanics, Shrodinger's cat, cellular automata, developmental biology ....). Forgive me if I mentioned someone's completed project that I am unaware of.
Best, David
On Thursday 29 November 2007 7:04 pm, David Corking wrote:
My mental model for arithmetic is a clock face, which is very clumsy in base 10 (and worse in base 16!)
A clock face has many interesting properties too. It incorporates the concept of magnitude (countables) and angles (directions/turns), "feeling" time (kairos) and periodic time (chronos).
1. The clock face has two hands of different magnitudes - small and big 2. The small hand moves in steps of one. The big hand moves in steps of five. 3. Reading a clock means reading the magnitude traversed by the small hand and then the magnitude travelled by the big hand. 4. Even though the "magnitude" of big hands falls to zero, the time is larger because the "magnitude" of small hand has increased (concept of place value). 5. The hands move but still stay in the same amount of space. This turning around a pivot is an "angular movement". (Note: Alan's car demo shows how accumulation of linear and angular movements leads to a circle). 6. The angular separation between small and big hand makes interesting shapes. When they are farthest apart, it is like someone cut the clock face into two same pieces. When they are like room corners, then you can have four such pieces. 7. The clock chimes whenever the big hand points "straight up". The big hand "triggers" the sound. (The concept that an event is triggered when a specific combinations of events happen is the basis of kairos. A seed remains dormant till rains arrive to germinate. Kairos has no "magnitude" between event occurrences. A ten-minute wait in a long queue feels like an hour while a hour-long video game session feels like a minute). 8. The thin red hand (second hand) moves very rapidly and makes a regular ticking sound like water dripping from a faucet. Our heart races when exercising or when scared, but red hand always makes sixty ticks to complete one turn. (tick-tock time is chronos time. It is not subjective and involves magnitude. Pulse beats or dripping droplets are approximations. Galileo used his pulse to time chandelier swings in a church).
I will stop here and hope you got the drift. A first-grader amazed me one day by reading out the clock correctly. With my curiosity provoked, I got her to explain the process to me gradually over the next few days. The language may come across as a bit strange because I tried to use her own words as much as possible.
Subbu
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