"Not fit for purpose"

[Guest]

And another one.

The keyboard both main & the left numeral patch do not have a divide button. Amazing

A serious of buttons to press to get one to get the divide symbol. Such is modern life.

[Dave Ward]

I was brought up on traditional Maths - Log Tables,Slide Rules. I learnt to use MathCad, when I was 45 - after that I forgot how to do mental arithmetic! I used a calculator to do simple addiction & substraction! When I retired I rediscovered mental arithmetic & guesstimation - I didn't have access to fancy math programmes! I'm afraid I strongly believe that Kids shouldn't use calculatulators, or computers until they're 10 - then go straight to hi tech maths!
Dave

[Guest]

I- then go straight to hi tech maths!
Dave

Wow that depends on the person & their intelligence.

Plus the aptitude for maths which varies so much in those who are intelligent.
My eldest daughter highest intelligence among the 14 in the family. But she
struggled intensely with maths. Only her own determination to get to grips
got her thro. It did not come easily.

My psychic. Why learn to drive an F1 racing are if you are only going to drive
an ordinary road car.

[Tim Marlow]

I was brought up on traditional Maths - Log Tables,Slide Rules. I learnt to use MathCad, when I was 45 - after that I forgot how to do mental arithmetic! I used a calculator to do simple addiction & substraction! When I retired I rediscovered mental arithmetic & guesstimation - I didn't have access to fancy math programmes! I'm afraid I strongly believe that Kids shouldn't use calculatulators, or computers until they're 10 - then go straight to hi tech maths!
Dave

I agree here, and it certainly how my daughter was taught. She’s 22 now, by the way, so it wasn’t that long ago. Calculators were not allowed until after she moved up from Junior school.
I was very much taught this way, but slide rules and log tables were part of the O level curriculum, not junior school. Calculators didn’t really make an appearance until I was about sixteen….before that they were simply too expensive for the average kid. I remember my first Casio desk top calculator. It was well named. If you’d put a leg on each corner it would have made a decent sized desk LOL.
The most important thing a kid can learn pre-senior school (or at any age) is to include all of their working for an answer. What is important is how they derive that answer, not if the answer is actually correct.

[Guest]

I agree here, and it certainly how my daughter was taught. She’s 22 now, by the way, so it wasn’t that long ago. Calculators were not allowed until after she moved up from Junior school.
I was very much taught this way, but slide rules and log tables were part of the O level curriculum, not junior school. Calculators didn’t really make an appearance until I was about sixteen….before that they were simply too expensive for the average kid. I remember my first Casio desk top calculator. It was well named. If you’d put a leg on each corner it would have made a decent sized desk LOL.
The most important thing a kid can learn pre-senior school (or at any age) is to include all of their working for an answer. What is important is how they derive that answer, not if the answer is actually correct.

We had one teacher, who I will never forget, she taught us in what was the senior school.

Slide rules & bead the only calculators.

But she taught us to use our brains. I still use it . How to quickly multiply divide add subcontract
using simple methods. Not 6*7. but large numbers & complicated. Add things subtract numbers then add.
So simple in a great number of cases quicker than an adding machine.

Almost working in reverse to the normal method. She had the whole class practicing & the results were amazing.

Laurie

[Gern]

You want a calculator with RPN mode. In that, you would do [ICODE]2 + 2 ÷ 2[/ICODE] with the desired answer being 2 as [ICODE]2 2 + 2 ÷[/ICODE] — that is: here’s the number 2, here’s another 2, now add them; here’s another 2, now divide the previous outcome by that. Whereas for the outcome of 3, you would need to do: [ICODE]2 2 ÷ 2 +[/ICODE]. There is no need to remember which operation goes first: whichever you put first, goes first.

Really, it’s one of those things that I wish were taught in primary schools rather than the confused mess of the order in which to apply operators, that needs mnemonics in order for people to remember them.

I've not seen this RPN system before, but it strikes me as being just an alternative way of doing calculations either sequentially - just like the old fashioned bog standard calculator, or in 'scientific' order. You - the operator - are still left with the problem of deciding which method of entry will give you the answer you need rather than the answer the machine decides you need.

Incidentally, the article you have linked to also makes the point that this method is more difficult to learn.

I do agree that the idea of sequencing multiple calculations is a skill that needs to be taught early, but my jury is still out on which method is best - sequential or scientific. Both are equally valid and will give the correct answer if used properly, although sequential calculation does seem slightly more natural.

[Gern]

Hi Dave
i understand all of your points here, and think the issue lies with the rigid application of the BODMAS concept. To me, maths is a language, and to work through a string calculation carrying out certain operands before others is absolutely counter intuitive. BODMAS seems to exist to allow lazy question compilation. It has no real basis in logic. In your first example the answer given by the syntax as written is, and only can, be two. To me, if I am supposed to get three as an answer I have to read the “sentence” backwards! If the question is to generate an unambiguous answer it must be compiled more accurately, as Laurie indicates.

I agree that sequential calculation seems more natural, but wasn't BODMAS introduced originally as an attempt to clear up any possible ambiguity?

[Gern]

Interesting put in my computer calculator it comes up with the correct answer.
Laurie

Which computer calculator are you using Laurie? My PC has two types of calculator - the normal default one (sequential) and a scientific one (BODMAS). They give different answers.

[Gern]

I'm getting a nose bleed!

Thank heaven I made enough pennies for an early retirement simply by knocking nails into bits of wood.

The only calculation I ever needed was if I could finish a roof in time before the British Legion Bar opened.....:thumb2:

Nice to see some of us old farts using maths as it was originally intended - to give us usable, practical answers to everyday problems!

[Gern]

But can you still spell BOOBS on it?

And 5407708! Read it upside down.

[Gern]

My biggest bug-bear as a result of modern education is the total lack understanding around Metres Squared and Square Metres.

I got asked that a few times by various tutors in the vocational subjects at college. Alas, it's not really a maths question. It's English and just a matter of semantics. None of them could tell me that they used the terms unambiguously - ie always using metres squared when talking about the area of a shape 2m x 2m = 4 metres squared. If they can't be consistent, why should I be?

[Gern]

Hi Dave
i understand all of your points here, and think the issue lies with the rigid application of the BODMAS concept. To me, maths is a language, and to work through a string calculation carrying out certain operands before others is absolutely counter intuitive. BODMAS seems to exist to allow lazy question compilation. It has no real basis in logic. In your first example the answer given by the syntax as written is, and only can, be two. To me, if I am supposed to get three as an answer I have to read the “sentence” backwards! If the question is to generate an unambiguous answer it must be compiled more accurately, as Laurie indicates.

You have a good point Tim, but why then do we supply our kids with tools that use both methods, one which will give a correct answer and one that gives a wrong answer? And how about tools that don't give an answer at all?

[Gern]

I've not seen this RPN system before, but it strikes me as being just an alternative way of doing calculations either sequentially - just like the old fashioned bog standard calculator, or in 'scientific' order. You - the operator - are still left with the problem of deciding which method of entry will give you the answer you need rather than the answer the machine decides you need.

Incidentally, the article you have linked to also makes the point that this method is more difficult to learn.

I do agree that the idea of sequencing multiple calculations is a skill that needs to be taught early, but my jury is still out on which method is best - sequential or scientific. Both are equally valid and will give the correct answer if used properly, although sequential calculation does seem slightly more natural.

I meant to ask. How do you enter 2 2 + 2 ÷ ? Is it 2 space 2 space + space 2 space ÷ ? If so, that''s a lot of extra buttons to push. If not, how do you distinguish between 2 2 and 22?

And would this interfere with the idea of space notation when writing ordinary numbers?

ie 102 represents 1 hundred + 0 tens + 2 units. We wouldn't write it as 1 space 2. With printed numbers I suppose that could work, but it would be an absolute nightmare for handwritten calculations. Anyone with poor writing would be unable to distinguish between 1 2 and 12.

[Tim Marlow]

You have a good point Tim, but why then do we supply our kids with tools that use both methods, one which will give a correct answer and one that gives a wrong answer? And how about tools that don't give an answer at all?

For the same reason we teach them SI units, then ignore them in real life, or standard chemical notation, and use old archaic names. Try finding 10M HCl in a builders merchants. No chance! You’ll probably find 3.5N spirit of salts though. It even happens in scientific establishments and with scientific chemical suppliers. It is just not seen as really important. When I started work at Porton I had to take myself back to school to find out what “normals” were! I had only ever been taught molarity as a measure of chemical concentration so didn’t have a clue what it was.
For another example, ask almost anyone how long a centimetre is and they will say ten millimetres. The answer is really one hundredth of a metre because the metre, not the millimetre, is the base SI unit of length.
Last example, how many times have you been asked to fill in your weight on medical forms? The correct answer should be given in Newton’s, because weight is a product of mass and gravity. What they really want is your mass, which is given in Kilos! Weight changes minutely depending upon height above sea level, mass is a constant.
BODMAS only seems to have appeared in mainstream teaching once early calculators were coomonplacel. These crude early devices could only carry out instructions as they were keyed in by the operator, so this was brought forward to ensure consistency during use. Before that it was the domain of those interested in that part of mathematics.
By the way, my phone and IPad both give the “BODMAS correct” answer to your question…..so at least their electronic appendage is correct according to standard tuition, if not to logic as I was taught it.
Really interesting subject, by the way!

[dave]

Although we had calculators at school, we were taught with slide rules and were only allowed to use calculators in the O’level year. The idea being we knew how to do the calculations and how to do rough estimates so we knew if the calculator gave a stupid answer.
you would also be suprised how high you can stack chairs, the year above me on their last night stacked all the chairs from the assembly hall into a massive pyramid in the quadrangle, took a photo, and put the chairs back. Left the photo on the headmasters place at breakfast.