Showing posts with label math-multiplication. Show all posts
Showing posts with label math-multiplication. Show all posts

Wednesday, 2 April 2014

Maths as a Pleasurable and Sociable Pursuit

Can maths ever be a pleasurable and sociable pursuit for a normal young child?  The answer appears to be a positive "yes".

To start with, maths is done slightly unconventionally in our house.  Instead of following a specific curriculum, we tend to work on a certain topic that interest us at any given moment.  As it turns out, we have been spending a fair bit of time on simple arithmetic in the past few months, as I said we would.

The independent aspect of maths learning here takes place when Tiger reads maths-related books on his own, such as the ones pictured below:


He enjoys reading them repeatedly but he doesn't want me to get involved with his reading.  When I saw what can be done with these books, I offered to work through the problems with him but my offer was politely turned down.  Somehow, despite (or maybe, because of) very little involvement on my part, Tiger has found his own pleasure in maths and an inner confidence to put the following notice up outside his room:

Note the happy face on his selfie.

Since he became the self-appointed 'consultant maths guy' in the house, Tiger has been pestering me for "worthy" maths problems.  Sometimes I show him maths puzzles from this book, which he attempts to solve on his own before working collaboratively with me to find different solutions.


At other times, he sets himself the target of working through the problems/puzzles in the following book:


Once again, he doesn't want me to get involved in his work here.   The reason he gives is that he can check the answers at the back of the book, and since the solutions are also provided, he can figure them out by himself.  Fair enough.  Nevertheless, Tiger is happy to share his approach:  he raced through the "Easy" section within an hour and is a quarter of his way into the "Hard" section.  There are some concepts in the "Hard" section that he hasn't come across yet, which he wants to figure them out by himself so he is working on one problem a week -- he reads the question on Monday, thinks it through for the rest of the week, then solves the question on Friday.  When asked why he needs a whole week for one question, his reply is that he wants to "think through all possibilities and get it right" (his words).


Tiger will not have engaged himself in the above activities if he didn't derive some pleasure from solving mathematical problems, mostly on his own but sometimes collaboratively with me.  Recently he has progressed to sharing his mathematical discoveries (mostly applications of numerical patterns) with Tortoise and I by giving us mini lectures in the evenings.  Again, to give lectures as a way of showing what he has learnt is entirely his own idea; Tortoise and I are usually given a few hours' notice to attend a lecture in the evening.  It suits us fine since we are keen to know whether and what Tiger is capable of learning on his own.
When learning to learn is given a higher value than the learning of information, then the educational system will have made a big step in the direction of enabling children to be autonomous students (in the general sense) for life.  By encouraging the exploratory aspects of learning, its excitement and inherent satisfaction can be generalized into an approach to all life experiences; learning then is not associated only with school and the classroom, but becomes a part of living.
-- Joan Freeman, Gifted Children, page 272

Tiger's maths lectures so far have been very interactive and engaging.  He usually starts off with an example of how he applies his method to a problem, then he explains how he arrives at his method, which is followed by a very lively Q&A session where he is often challenged to defend his new-found techniques.   He is thrilled when his discoveries withstand the grueling challenges thrown at them from the floor, yet he is also able to find the grace and courtesy to accept that a few of his conclusions have been wrong due to careless calculation mistakes or a logical oversight.
Gifted children can jump to conclusions by a process of brilliant mental leaps, which are wrong because of lack of information.  In a reassuring 'safe' exploratory classroom, mistakes are part of the process of learning; they are not 'failures'.
-- Joan Freeman, Gifted Children, page 273



I find it interesting to observe that Tiger appears to be more receptive to learning maths in this way rather than in the traditional instructional way.  To my mind, the traditional way is a very quick way to learn something -- someone tells you the 'right' way to do things and you just practise until you master it.  However, that's not how Tiger likes to learn, at least where maths is concerned.  His preference for learning through discovery takes a lot longer, and can sometimes lead him down the wrong path where he has to back track and relearn some of what he thought he knew, but he won't have it any other way.  Luckily for him, being homeschooled gives him the time, space, and support to do just that.  Can you imagine how his approach to learning would be interpreted in the mainstream schools?  "Unteachable" is a word that comes to mind, but that applies only if the teacher has very fixed ideas about what teaching and learning look like.  A child like Tiger may appear to resist formal instructions, but that doesn't mean he lacks the ambition, enthusiasm or capability to master his chosen subject matter.  The challenge, then, is for the adult to get to know the child so well as to be able to provide the right kind of support at the appropriate level.
The teacher of the gifted child is in a particularly important position - not there to demonstrate her superior knowledge or to show what a good actress she is, but to enable children to grope and leap towards understanding.  It is important that the bounds of that understanding are determined by the characteristics of the pupils, not of the teacher or the school.
-- Joan Freeman, Gifted Children, page 273

Besides the in-house lectures, the more obvious social aspect of Tiger's mathematical pursuit comes in the form of maths circle.


We don't attend these very often due to their infrequency, but we enjoy them immensely every time we go.  The maths circle informs us of a number of things:
  • that mathematicians work both alone and collaboratively with others to solve problems;
  • that real maths problems are multi-dimensional and require an ability to connect various topics that are currently taught in segregation;
  • that it's fine to spend a long time on a single problem;
  • that sometimes the solution doesn't come even after a long time of thinking.

At the latest maths circle, Tiger spent the entire time there trying to solve one maths problem, and that was with the help of two maths undergraduate students.  I watched from a safe distance (far enough not to interfere) as the three of them racked their brains for nearly two hours, trying to grapple with that problem using various hypotheses, numerous discussions, and multiple experimentations.  Although he did not solve the problem by the end of that session, Tiger came away feeling exhilarated and asked to attend more of such events.

Between this and a method that produces children who "can't wait to be done with boring maths", I'd be happier to take the former even though it looks nothing like the time-honoured (although not necessarily successful), conventional way of teaching and learning maths.

The following documentary addresses directly the American public, but the issues discussed are just as applicable to the UK and indeed, to anywhere in the world that subscribes to the "standards" of mass schooling:




This post is linked up to:
  1. Hip Homeschool Hop - 4/1/14
  2. Entertaining and Educational - West Africa Study
  3. Collage Friday: Como Se Dice?  Dad's in Honduras
  4. Weekly Wrap-Up: The One In Which Spring Sprang... or Is It Sprung?
  5. The Homeschool Mother's Journal (4/5/14)

Thursday, 9 January 2014

When Everything Adds Up

Now that we are very familiar with straightforward addition, let's try our hand at finding the sum of all the numbers in a range, say from 26 to 765, without using a spreadsheet or calculator?

In order to learn the technique to work out sums of the above nature, let's start with the basics.

Q1: Find the sum of all whole numbers from 1 to 10.
The answer (55) can be easily worked out mentally or by writing the sums out on a piece of paper, but we are trying to learn a logic that will enable us to work out sums of any range.

To do this, I used a piece of cotton string and attached each individual number card 1 to 10 with paper clips.


I then asked Tiger what he would do, besides using mental calculation, to find the sum of all the numbers from 1 to 10.  He removed all the numbers from the number line, so that all ten numbers were accounted for, and paired them up into equations with the same sum total of 11 each:

            1 + 10 = 11
          2 +  9  = 11
          3 +  8  = 11
          4 +  7  = 11
          5 + 6   = 11


Once Tiger set the five equations out on the floor, it was obvious that the sum total would be 5 x 11 = 55, which tallied with his mental calculation.

I then reset the number line with numbers 1 to 10 again, and asked Tiger whether he could solve the problem in a slightly different way, i.e. using a total that is not 11.  When Tiger couldn't think of any other way after a while, I suggested changing the total to 10.  This way, the logic behind the solution is the same as before, except that there are a few extra steps:

When we set the total to be ten, the number 10 is removed first from the number line.  That is followed by the pairing up of numbers that make up ten.  When the pairing is completed, you will find that the number 5 is left unpaired.


The pattern will look like this:
                  10 
          1 + 9 = 10
          2 + 8  = 10
          3 + 7  = 10
          4 + 6  = 10
                5

Therefore, the final summation to find the answer is:
           (5 x 10) + 5 = 55

Between the two methods (sum to 11 versus sum to 10), I personally lean towards the one with sum to 10, but Tiger prefers what he considers to be the more straightforward method of summation to 11.  As you've seen from the above, both are equally valid so the choice depends on what makes the most sense to the child.



Q2: Find the sum of all whole numbers from 12 to 30.
We tried another exercise to check whether Tiger has understood the logic/technique to apply it to another question.


Tiger had a choice of using whatever method that worked best for him.  He chose to do the first method, i.e. the one where the first number (12) was added to the last number (30), and so on.


By doing so, he found that he had the 'middle number' (21) left unpaired, so he put it at the top of his layout so to ensure that he did not forget to add it to the final answer later on.


The pattern that he found was this:
                   21
          12 + 30 = 42
          13 + 29 = 42
          14 + 28 = 42
          15 + 27 = 42
          16 + 26 = 42
          17 + 25 = 42
          18 + 24 = 42
          19 + 23 = 42
          20 + 22 = 42

Therefore, the final summation to find the answer is:
           (9 x 42) + 21 = 399

At this point, I introduced another concept to Tiger: how to find the number of items (in this case, the number of pairing) from one number to another.

By counting or just looking quickly at the layout above, we determined that there were nine sets of pairings that summed up to 42.  Counting is fine until the range gets too large.  Therefore, I asked Tiger how he would determine the number of pairings without counting.  When he started to experience some difficulty, I asked him to think about how he would determine the number of pages he has read in a book, say from page 1 to 10.  After first he said the asnwer would be nine pages since 10 - 1 = 9, but when he quickly realised that the correct number was ten.  That was a bit puzzling.  I then asked him how many pages he would have read had he read from pages 2 to 11.  Again, answer is ten, but if he had applied the simple subtraction method of 11 - 2, he would get only nine.

By now, Tiger saw the logic behind this: that the number of items in a range is the simple subtraction of the last and first numbers followed by adding one more to it.  I helped him with the next step by putting his explanation into a simple formula:
        the number of items in a range = last number - first number + 1

We then verified our formula against the two examples above by first applying the numbers to the formula followed by verifying our answers with visual counting.


Q3: Find the sum of all whole numbers from 27 to 68.
Now it's time to see whether Tiger really knows what to do, so I set him the following exercise and left him to solve it himself:


Tiger proceeded with it methodically:
First, he laid out all the numbers in pairs so that every number on the number line was accounted for.  The sum of each equation was 95.  The pattern that he made was:
           27 + 68 = 95
          28 + 67 = 95
          29 + 66 = 95
          30 + 65 = 95
          31 + 64 = 95
          ......
          45 + 50 = 95
          46 + 49 = 95
          47 + 48 = 95


Using the formula he learned above, Tiger found out that there were 21 sets (48 - 68 + 1 = 21) of equations that each added to the sum of 95.  Therefore, the final answer was
      21 x 95 = 1995.


Once Tiger has got the hang of it, he is now able to find the sum of all whole numbers from different ranges.  I gave him a few extra questions to work on:

Q4: Find the sum of all whole numbers from 5 to 100.


Q5: Find the sum of all whole numbers from 36 to 205.


Q6: Find the sum of all whole numbers from 12 to 156.


Q7: Find the sum of all whole numbers from 4 to 237.



Having said all of the above, it makes sense to acknowledge that we are dealing with elementary maths, which is essentially concrete, so perhaps not...


Watching the clip above led us to ponder more with about the following:


If one gets into higher, more abstract maths (as the following videos show), then the concrete number sense that we have just spent so much time learning are nullified, similar to how conditions of quantum physics defy many common laws of physics.



But I'm not worried about that just yet.  I'm happy that Tiger is enjoying the concrete aspects of maths at the moment.


This post is linked up to:
  1. Entertaining and Educational - Atoms
  2. Collage Friday - No Spend Month, Marriage, Menus, & Miscellany
  3. Weekly Wrap Up: The One Where Dad Was Home
  4. The Homeschool Mother's Journal {January 11, 2014}
  5. Hip Homeschool Hop - 1/14/14
  6. Math Teachers at Play #70

Thursday, 7 November 2013

Out of Love

I'm falling out of love with Fred.

Two summers ago, we spent a few weeks working through the Life of Fred elementary series books A to G.  I wasn't overly keen about it in general but Tiger was tickled by its humour so we decided to keep the last three books (H to J) for this summer.


We worked on Book H a few weeks ago but I am even less impressed with it now than I was two summer ago.  The format of the book is still the same as before, the humour is still the same, so my guess is that the change in my opinion of this series is due to a combination of my increased leaning towards a "living maths" approach and an increased understanding of how Tiger learns.

Two instances in the book stood out for me: the first was when we made a pile of multiplication quiz cards based on Book H's suggestion, to be used at the beginning of each lesson/chapter as a quick mental review.  Making index cards to be used as pop quiz is a fine idea but it doesn't work for us for a few reasons:
  1. Tiger already knows his times tables so this step is redundant.
  2. There is no clear derivation of how a x b = c.  It becomes another bunch of maths facts to memorise, although the book takes a longwinded way of storytelling to have you memorise those facts.  I hate memorisation, as does Tiger.
  3. Tiger learned multiplication through understanding the relationships between quantities, rather than memorising sets of facts, so we are not thrilled about flashcards.

The second is how the book introduced long division.  While the reader gets a clear example of the steps to long division, the concept behind carrying and remainder isn't clearly explained.  I felt increasingly uncomfortable at teaching Tiger the steps to long division without having him understand why that is so.  The lesson became less of discovery and more about memorising a formula "first do this, then do that, followed by this".  Memorising yet again.  Sure, Tiger can now do long divisions on demand, but I am not happy that he is learning maths through memorising.

Some people might wonder why I am making a fuss here, given that Tiger has no problems doing long divisions whatsoever.  My objection is directed at the way it is being taught, that the method reminds me too much of rote learning, albeit a glamourised one.  I'm sure we can do better than this.

The remaining two books of the elementary series are being put to the back of the shelf.  We might use them next summer, or we might not.  We certainly aren't missing them.

Thursday, 11 April 2013

Map coordinates

After learning about map scale, the next logical thing to learn is to read map coordinates.  Tiger read the following book for introduction to the topic:


As an introductory exericse, Tiger worked through a page to identify the points on a grid map with numbers on the x-axis and alphabets on the y-axis.  This was very straightforward because Tiger is already familiar with reading maps with such coordinate points.


Next, I introduced Tiger to another way to represent coordinate points -- using numbers in both the x and y axes.  This was slightly confusing because now Tiger had to figure out which axis was represented by the respective numbers.

For this exercise, I had Tiger draw out the X-axis and Y-axis, then he was to list the coordinates of the points that I put on the grid.


This was followed by applying our understanding of coordinates to drawing, first by linking various pre-set coordinates into straight lines and forming a shape on paper.


Next Tiger got to apply what he had learnt so far onto graph papers.  He was to identify various points on the graph paper based on a set of coordinates that I verbally read out to him.


These form the smaller shape on the paper.  Once the original, smaller shape was drawn, I gave him a multiple which he was to use to draw the bigger shape.


Here is another application of scaling up:


The next application was slightly more complicated than the ones before.  Here, Tiger had to:
1) plot the points on the paper;
2) reflect the figure on the y-axis;
3) learn that the equation for a straight line between two given points and which goes through the point (0,0) is y = -x.
4) apply his knowledge of rotational symmetry to plot the points of the final figure which was symmetrical to the original figure on the line y = -x.


Tiger played the following games to conclude his study of the coordinates:
  1. Archery
  2. Lost
  3. Cops and Robbers


The lessons come from the following books:



This post is linked up to:
1) Look What We Did!
2) History and Geography Meme #69
5) Homeschool Mother's Journal: April 12, 2013
6) Hobbies and Handicrafts - April 12
7) Collage Friday - Part Time Unschoolers?
8) Homeschool Review
9) Weekly Wrap-Up: The One with the 2:1 Conference 2013
10) Math Monday Blog Hop #95
11) Hip Homeschool Hop - 4/16/13

Wednesday, 20 February 2013

Playing with numbers

Every now and then, Tiger and I get slightly bored by how maths is done at home and both of us want to make changes to how we do maths.  It seems that we have come to a point where I am comfortable with Tiger's grasp of the fundamental concepts in elementary maths that we can afford to be more adventurous in taking detours from our usual maths routine.

Rather than playing random maths games (nothing wrong with that), I am inclined to take a thematic route in this area.

We started with the topic of "numbers".  The first activity we did was to make a number chart puzzles.  This was intended to help cement the concept of consecutive whole numbers.

First I printed off a number chart of whole numbers from 1 to 100, and had Tiger block out different sections with coloured pencils (to be cut out later) to make the puzzle.


The first one with consecutive whole numbers was too easy, so we did another in multiples of 10.



That was just warm-up.  Next, we played all the games found on this page.  These games were fun refreshers for Tiger in the concepts of multiples and odd and even.  His favourite game was Read My Mind.




Tiger and I found more challenges and satisfaction at solving maths puzzles that require a combination of different skills, which involve mathematical thinking as well as visualisation skills.  The four puzzles we worked through together were:

1. Make 37 (main concept: odd and even numbers)

2. Mystery Matrix (main concept: multiplication)


3. Consecutive Numbers (main concept: addition and subtraction)


4. Magic Vs (main concept: odd and even numbers)


We love these maths games!  They tend towards the abstract side of mathematics, which helps if you have strong maths foundation and visualisation skills.  Manipulatives don't work so well to solve such puzzles.  Additionally, it is also a very involved process for parent and child in that we would discuss, debate, and argue about how we would approach the problem, before solving it together.  Discussion is a big part of the learning process for such puzzles (at least in our case), so I don't think these puzzles will be as effective without parental involvement.  We find the process to be very interesting and mutually beneficial in that Tiger can apply his intuitive problem-solving skills while I can observe and learn more about the way he thinks, which is very different from my thinking process.

Tiger can pretty much hold his own in our maths discussions now due to his strong intuitive and visualisation skills in solving maths problems, while I bring logic and methodology to the table.  So far, this has worked very well for us.

Another number game that Tiger has taken an interest in is Sudoku.  He takes the book with him and solves a few puzzle on the go each time we are out and about.




This post is linked up to:
1) All Year Round Blog Carnival: Winter 
2) Hearts for Home Blog Hop #5
3) Homeschool Mother's Journal: February 22, 2013
4) Hobbies and Handicrafts - Feb 22
5) Collage Friday - Family, History, and More
6) TGIF Linky Party #64
7) It's a Wrap
8) Weekly Wrap-Up: The One with the Busy Break Week
9) Share it Saturday - Feb 23
10) The Sunday Showcase - 2/23/13
11) Math Monday Blog Hop #88
12) Hip Homeschool Hop - 2/26/13
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