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  1. #16
    rrich Guest

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    Let me interject a couple of things here about math.

    In the early school years, a work sheet was handed out with about 100 simple arithmetic problems. If I got one wrong it was "Do the whole sheet over again". Not exactly the best way to create enthusiasm in math.

    It wasn't until I had retired and was taking a Community College level class in building a coffee table that I heard, "That's not quite right. Let me show you how to fix it." I can say that I learned.

    As for the scientific calculator issue. CASIO makes an fx-260 solar.

    Casio® FX-260 Solar Scientific Calculator | Staples®

    Here they cost about $11 US. The calculator has all the trig functions and the calculator does square roots and fractions. Of course you blokes are of the metric persuasion and don't need fractions.

    The calculator is an algebraic calculator or does the calculation in algebraic mode. (7+3x7=28 and not 70) The calculator is solar powered and if you have enough light to read the display you have enough power to do calculations. I've bought several from 'Staples', a US office supply chain.

    If you can't get the calculator there, lets work through e-mail or PM and we'll work something out.

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  3. #17
    Join Date
    Sep 2004
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    Brisbane
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    Quote Originally Posted by labr@ View Post
    Yeah, but apart from computers, the internet, Google searches, woodworking machinery, tools and the GPS what has mathermatics ever done for us? NOTHING!

    Actually I have used algebra a lot since leaving school, especially when I started using spreadsheet programs. Also use trig frequently in my job and all kinds of calculations in woodworking. Can't recall using calculus though.

    Good thread, well done for posting Chook.
    Calculus is one of the most practical of the branches of mathematics. It is the mathematics of change and most of our electrical tools run AC current where the voltage continually changes. Calculus is vital but the application is done by an engineer somewhere and we get to use the products. Another, not Woodie, example. a large road construction company was building a road in far west Quensland. They stored their fuel in vey large, oddly shaped containers which were periodically refilled. But they suspected that the supply company was ripping them off. What they wanted was a method of determining how much fuel was in the containers from a simple measure of depth. Given the odd shape of the thing, this was not straight forward. The solution was a basic application of integral calculus. Very practical but the chaps who used the results probably never suspected that calculus lay behind it.

    Thnak you you by the way for your kind words. I was very hesitant to put this thread up on the forum. I thought it might annoy people.
    My age is still less than my number of posts

  4. #18
    Join Date
    Dec 2008
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    Yarra Valley Vic oz
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    Quote Originally Posted by chook View Post
    Another, not Woodie, example. a large road construction company was building a road in far west Quensland. They stored their fuel in vey large, oddly shaped containers which were periodically refilled. But they suspected that the supply company was ripping them off. What they wanted was a method of determining how much fuel was in the containers from a simple measure of depth. Given the odd shape of the thing, this was not straight forward.
    Were the containers that were being filled level, was the dip stick in the center of the container?

    Why couldn't they work out the fuel delivery from the flow meter on the delivery truck?

  5. #19
    Join Date
    Feb 2005
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    1,389

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    My thoughts on what is bedtime reading:

    Before language there was counting.

    History of mathematics through the ages is a study in itself.
    Base 12 (clocks, dozen, compass, miles and acres) base 2 (computers) base 10 (easy maths, currency)

    Magic is basically statistics.

    No one (well hardly anyone) fully comprehends time or size (small and large)

    Greg

  6. #20
    Join Date
    Feb 2015
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    Hobart
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    77
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    647

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    Quote Originally Posted by snowyskiesau View Post
    I recently started on a pair of saw horses with splayed and angled legs with a I beam style top. it took me an embarrassingly long time to work out the geometry for the cuts.
    On the plus side, there's little chance of me be able to cut accurately to the calculated lines so I can blame errors my woodworking incompetence rather than my mathematical ineptitude.
    Join the club I think it is to do more about the visualisation of a three-dimensional problem rather than "maths". My own pair of sawhorses don't wobble but the angled joints are pretty sloppy!!!

    I'll try to make another set soon(?)

    yvan

  7. #21
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    2 + 2 = 5

    for greater values of 2

  8. #22
    Join Date
    Jun 1999
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    Westleigh, Sydney
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    It's amazing what a difference a good teacher can make. When I was studying surveying, it wasn't unusual to have 3 or 4 of us plus one of our lecturers (mostly practising surveyors) hanging around after class, drawing lines on a motor cycle helmet or such, arguing out a spherical trig or some other problem.

    Really, maths is mainly about recognising patterns, thinking logically and being able to identify the problem. One of the things I learned early on was "if you can't calc it, plot it. If you can't plot it, calc it." each will, in their own way, help you to identify the problem.

    Also, it's important to be able to do a mental reality check. If it looks wrong, it probably is. You just have to know what 'wrong' is.
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  9. #23
    Join Date
    Oct 2005
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    Wonga Beach North QLD
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    Mathematics is a funny thing. Blocklayers use it all day long (but please don't tell them).
    When you have to physically move tons of blocks each day, working out how many, what type and where to put them (math) can save lots of work.
    If you under-load on scaffolding, you have to climb down and re load.
    If you over load, you have to move the blocks again (and again), so getting the math right saves a LOT of work.
    And there's 9 or more different types of concrete block in a standard house, so it's not just plain 'blocks' to work out.
    And working out bond involves dividing measurements by 400 to work out how many blocks long a wall is and which way to lay the corner/end blocks (Header or Stretcher)
    But (most) blocklayers claim they are hopeless at math, and computers frighten them.
    A classic example is marking and cutting the blocks in a raking gable.
    The standard way is to erect a 'stick' at the apex, run a string line down the rake, lay the blocks up to the line, then measure and mark each block to the line, pass it down (from scaffold), have it cut then back up the scaffold to be laid. In 1987 I wrote a program to work out all the cut block dimensions so they can be pre-cut and numbered. It also matches off-cuts, so you can save a LOT of (expensive) cutting.
    New Concrete Block Gable Cutting System With Off-cut Matching - Metric
    It's at least twice as fast (3 times once you're used to it), and MUCH more accurate than the 'stick and string' method.
    But very few blocklayers will use it, because it involves computers (and computers are like mathematics).
    Another example is the template-less arch system. You can build a block arch without using a support template, but again, it involves computers, so it's rarely used.

  10. #24
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    Quote Originally Posted by Robson Valley View Post
    For some years, we had students doing population data analysis in Biology lab periods. Pool the individual data and work with data sets with thousands of entries. MS Excel was adequate.
    What we observed was that the students cannot mentally estimate an answer. Because the calculator says so, because the maths app says so, they can't comprehend a gross error when they make one.
    Excel had an advantage there. My problem is that I was taught all sorts of useful geometries but long before I had any use for it. I resent that but re-learning what I need has been a useful exploration.

    Just so RV!!!

    I have always loved maths. Maybe because my father, who never attended high school, he was still a bloody good mathematician and would work things out in the clear borders of the newspaper!
    Dad was a first class bridge player and would work things out for which I used algebra.

    I remember being taught Euclidean geometry in primary school - not that We were ever told that's what it was. I well remember a couple of light bulb moments when I figured out how our 6th class teacher
    arrived at answers so quickly and how he used a string and a spike to mark out a softball diamond. Nothing was ever taught, I guess I just had a good osmotic brain coupled to my father's teachings on logic!
    I still use those lessons to this day and many people, especially the younger ones, are completelysurprised by what can be achieved using this type of geometry. In high school I did Tech drawing and this
    complements the geometry beautifully

    Unfortunately I went to a central school in NSW and this ended at 3rd year. No specialist maths teacher was to be had so basic algebra was as far as our maths education went. After moving to a fully fledged high school
    The algebra was supplemented with, statistics - a subject I LOVED - and trigonometry. No Calculus as I didn't have the necessary background. I did a basic calculus course a uni., but that was it.

    My senior high maths teacher had been a navigator in the air force during WW2. He was a tremendous teacher and a good bloke to boot. Bill was keen for us to uese estimations and approximations and then common sense
    when dealing with complex problems. I well remember a trigonometry problem that involved a boat being rowed under a bridge. We had to calculate the distance traveled and then the speed given angles and the height of
    the bridge above the water. I was astounded by the fact that all but my good self had arrived at a speed somewhere in excess of the speed of sound for the boat speed!! Of course everybody else was right - according to them -
    because I was the od one out. No commonsense!! No estimating or approximating!! The only time I ever saw Bill totally exasperated!

    I still do approximations when dealing with larger numbers, saves much time and many hassles. As a teacher I always taught my charges short cuts BUT only after they had a thorough knowledge and understanding of the processes.

    These days I couldn't do trig if my life depended on it. I"ve had no need to use it. Basic arithmetic and Euclidean geometry are my go to tools. I still do things in my head and will only resort to paper when in doubt.

  11. #25
    Join Date
    Dec 2014
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    Willunga, Australia
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    I know exactly how you feel. I cannot help myself either.

    Whether you know it or not every woodworker uses maths all the time in one form or another. Whether they recognize it as maths is irrelevant, it is maths. When you calculate the position of your shelves, when you work out the center of a work piece, when you calculate the width of a tenon, need I go on. It is all maths. The more you do it the easier it becomes. The more "tricks" you learn from old timers the more maths you learn.

    Personally I love maths, always have done, and I have also learned to recognise the principles (maths) behind the "tricks". I think many of us learned more in school than we think.

    Yanis

  12. #26
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    Even before we were 10 my brother and I would do page long sums of addition and subtraction for each other to do. Then we wokd check each others work. I figured I was always right lol

    Dave TTC
    Turning Wood Into Art

  13. #27
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    Quote Originally Posted by DaveTTC View Post
    Even before we were 10 my brother and I would do page long sums of addition and subtraction for each other to do. Then we wokd check each others work. I figured I was always right lol

    Dave TTC
    Turning Wood Into Art
    Hate to be a nitpicker Dave BUT a sum is the answer to an addition!!

    I've always been a bit pedantic about some things!

  14. #28
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    Always good to pedantic

    Dave TTC
    Turning Wood Into Art

  15. #29
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    I hated maths, I once asked a teacher why we had to learn this stuff, his reply was because you have too, instead of explaining what it could be used for.
    One instance at school, was that we all did a particular maths problem, which was marked wrong, do it again which I did, same answer, ended up doing it for home work, by this time I'm almost in tears as I always ended up with the same result, my mother worked it out, got the same answer as I did. In the end she wrote a note to the teacher asking her to work it out, result was the answer in the back of the book was wrong.
    One would think that if ALL the kids got it wrong and ended up with the same answer, something was wrong, not her because the book said it was X it must be X. I learnt more out of school than at school.
    Kryn
    To grow old is mandatory, growing up is optional.

  16. #30
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    Quote Originally Posted by Bedford View Post
    Were the containers that were being filled level, was the dip stick in the center of the container?

    Why couldn't they work out the fuel delivery from the flow meter on the delivery truck?
    They did not trust the supplier and so I suppose they did not trust his meters. At the time I thought it was an odd request to be honest, but the young engineer who asked me was a long way from support.
    My age is still less than my number of posts

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