Maths problem

26 minutes ago, Tommygilf said:

Older and non scientific calculators cannot do this. As my teachers said, the calculator can only provide the answer to what you input. Knowing multiplication comes before addition and subtraction (in this case), makes a material difference. 

Knowing how your calculator has been programmed makes the difference.

2 minutes ago, unapologetic pedant said:

Knowing how your calculator has been programmed makes the difference.

Is anyone disputing that?

23 minutes ago, unapologetic pedant said:

Knowing how your calculator has been programmed makes the difference.

Knowing how to do the maths is the difference, any help in doing the maths is good. Rules, guidelines, call them what you will, help people get the right result, that is surely a good thing.

Presumption killed many a man.

8 minutes ago, Tommygilf said:

The OP's example is precisely that. We had loads where there was a multiplication or division or indices written after an addition or subtraction in an equation where the whole point of the question was to assess whether you knew the order of priority as per BIDMAS.

The addition/subtraction would be in brackets. How else would (a + b)^c be written?

No student would think it meant a + b^c unless it were written as such. If anyone did, acronyms are unlikely to help. 

1 minute ago, unapologetic pedant said:

The addition/subtraction would be in brackets. How else would (a + b)^c be written?

No student would think it meant a + b^c unless it were written as such. If anyone did, acronyms are unlikely to help. 

Given how many people wouldn't get the correct answer for the OP, I dispute "no student".

32 minutes ago, Padge said:

Once again you miss the point of the OP. You are really struggling with the concept of explaining precedence. the people on here must have had a joint hallucination despite being miles, years and cultures apart.

I'm saying that students on a maths course will follow operational precedence by virtue of understanding the principles behind the notation they see on the page. Happens naturally, no need for stilted mnemonics. That's back-to-front teaching.

Doubt only arises when using a calculator. And the question is to the programmer not the student.

53 minutes ago, Padge said:

No, you seem to have missed my point of moving on to a new but similar concept of confusion. Go back and read.

Not unreasonable for me to wonder whether a post might be related in some way to previous posts.

You'd be marvellous on Radio 4's Round Britain Quiz.

29 minutes ago, Tommygilf said:

Given how many people wouldn't get the correct answer for the OP, I dispute "no student".

People got it wrong because of how it was written i.e. like a series of instructions for a computer.

It's clearly designed to provoke wrong answers. But similar calculations would not be written like that as questions in a maths text book.

2 minutes ago, unapologetic pedant said:

1. 'm saying that students on a maths course will follow operational precedence by virtue of understanding the principles behind the notation they see on the page. Happens naturally, no need for stilted mnemonics. That's back-to-front teaching.

2. Doubt only arises when using a calculator. And the question is to the programmer not the student.

Not unreasonable for me to wonder whether a post might be related in some way to previous posts.

3. You'd be marvellous on Radio 4's Round Britain Quiz.

On point 1, they would have had to be taught the principles by using simple rules, you don't learn written English by not being taught its strange rules, you can speak it nevertheless. You can say where, were and we're and not know the spelling but know the difference.

Point 2. The rules applied 500 years before calculators, they were understood and worked across nations.

Point 3. I will take that as compliment, but it may be an insult.

1 minute ago, unapologetic pedant said:

People got it wrong because of how it was written i.e. like a series of instructions for a computer.

It's clearly designed to provoke wrong answers. But similar calculations would not be written like that as questions in a maths text book.

It was not written as a series of instructions for a computer, far from it, in fact the opposite.

Again you fail to see the point.

44 minutes ago, Padge said:

Presumption killed many a man.

Presumptions about computer programmes or computer programmers are demonstrably unwise.

14 minutes ago, unapologetic pedant said:

Presumptions about computer programmes or computer programmers are demonstrably unwise.

I am a great believer of never trust what comes out of a computer.

What comes out depends on what has been put in.

You still presume that I am coming at this from a computer view, you are wrong this is about maths.

7 minutes ago, unapologetic pedant said:

People got it wrong because of how it was written i.e. like a series of instructions for a computer.

It's clearly designed to provoke wrong answers. But similar calculations would not be written like that as questions in a maths text book.

Its not written like a series of instructions on a computer. I was presented with several calculations like that in my education in textbooks.

Its designed to confirm your understanding of the principles in the absence of a scientific calculator.

7 minutes ago, Padge said:

On point 1, they would have had to be taught the principles by using simple rules, you don't learn written English by not being taught its strange rules, you can speak it nevertheless. 

There's copious philological evidence to suggest that we acquire language skills in our formative years through recognition of patterns that correspond to a sense of inherent logic in our brains. And that teaching the rules of grammar is an endless and ever more sophisticated series of fine-tunings to that initial development. Same rationale would apply to fundamental mathematical truth.

More artificial and much harder to learn a second language if the whole process is one of teaching and learning rules.

10 minutes ago, Padge said:

You still presume that I am coming at this from a computer view, you are wrong this is about maths.

Again, not so.

I long ago conceded that -48 is mathematically the correct answer. All my quibbles are pragmatic.

9 minutes ago, unapologetic pedant said:

There's copious philological evidence to suggest that we acquire language skills in our formative years through recognition of patterns that correspond to a sense of inherent logic in our brains. And that teaching the rules of grammar is an endless and ever more sophisticated series of fine-tunings to that initial development. Same rationale would apply to fundamental mathematical truth.

More artificial and much harder to learn a second language if the whole process is one of teaching and learning rules.

I learned maths by using it practically, having to use it practically meant I learned to use the rules, the rules I had been taught.

You can learn a language by speaking it when you have to, it easier if you have been taught the grammar of the language first.

9 minutes ago, Tommygilf said:

 I was presented with several calculations like that in my education in textbooks.

I wasn't. Or at least not that I can recall. And I've certainly never heard of BIDMAS/BODMAS/BEMDAS.

Yet still managed to get an A at O level and a B at A level.

15 minutes ago, Padge said:

I learned maths by using it practically, having to use it practically meant I learned to use the rules, the rules I had been taught.

You can learn a language by speaking it when you have to, it easier if you have been taught the grammar of the language first.

I believe rules only work when they correspond to an innate sense of logic. Persistent practical application builds on that foundation, inculcating habitual thought and action. Applies equally to language and mathematics.

32 minutes ago, unapologetic pedant said:

I wasn't. Or at least not that I can recall. And I've certainly never heard of BIDMAS/BODMAS/BEMDAS.

Yet still managed to get an A at O level and a B at A level.

I got an A*, little differences I suppose.

1 hour ago, Padge said:

It was not written as a series of instructions for a computer, far from it, in fact the opposite.

Again you fail to see the point.

I repeat my earlier repeated point that 8 - 8 × 8 + 8 would be written as 8 - 64 + 8 in a maths text book.

There would have to be a fabricated purpose in factorizing 64 to 8 × 8. Such as catching people out on their knowledge of operational precedence rules or highlighting discrepancies in computer programs. 

13 minutes ago, Tommygilf said:

I got an A*, little differences I suppose.

I suspect I'd be like a transwoman now. Struggle to pass.

1 hour ago, unapologetic pedant said:

I repeat my earlier repeated point that 8 - 8 × 8 + 8 would be written as 8 - 64 + 8 in a maths text book.

There would have to be a fabricated purpose in factorizing 64 to 8 × 8. Such as catching people out on their knowledge of operational precedence rules or highlighting discrepancies in computer programs. 

By that logic there would be no questions in maths textbooks because they are all fabricated for a purpose (to test a specific learned skill or process). Just skip that and have the answers.

1 hour ago, Tommygilf said:

By that logic there would be no questions in maths textbooks because they are all fabricated for a purpose (to test a specific learned skill or process). Just skip that and have the answers.

The only purpose of turning 8 - 64 + 8 into 8 - 8 × 8 + 8 for a question would be to test the "skill or process" of regurgitating some version of BODMAS/BIDMAS/BEMDAS.

Far better to allow knowledge of operational precedence to be continuously tested through recognition and observance of mathematical notation.

In general, I don't remember being asked to memorize rules. We were required to set out proofs. 

A search of the internet for mathematical rules of precedence gives over 4 million results. I haven't checked them all, obviously, but the number of times it starts with an example such as 4+3x2 or variant of is quite outstanding considering we have someone on here saying they know their maths but have never seen it (in a text book). 

Strange that something that doesn't exist is referenced over 4million times.

Not got the foggiest about the content in the first 4 pages …. so I thought I would tell you about my first Math class in High School in 1976.

Each High School class consisted of lads and lasses from three local Junior schools.  One Junior school was regarded as far better than the other two, including the one that I attended.  So in trying to work out what Math level the class was at she wrote on the board and asked ‘what is a+b’.

One third of the class raised their hand.  The rest of us had no idea what was going on.  My mate sat at my side whispered in a panicky voice ‘######, we are in the wrong class, we are supposed to doing maths now’.

P.S. This was also the same mate, who - in a Geography class - watched the Teacher draw the east and west coast of north England on the blackboard and ask the class ‘If this area is Yorkshire, what is the area to the west called’.  No one answered. The Teacher then said ‘They are our biggest rivals at cricket’.  My mate shouted out ‘The West Indies!’.  Mind you the Windies had just thrashed England 5-0.

Happy New Year to all.

3 hours ago, Padge said:

A search of the internet for mathematical rules of precedence gives over 4 million results. I haven't checked them all, obviously, but the number of times it starts with an example such as 4+3x2 or variant of  

That rather buttresses my argument.

And magically we now have a fourth variant of the incantation certified to unlock the mysteries of mathematics and open the minds of an otherwise innumerate global populace.

Any advance on PEMDAS?

4 hours ago, Padge said:

is quite outstanding considering we have someone on here saying they know their maths but have never seen it (in a text book). 

Haven't made any such claim. Only drawing on personal experience. And, to a considerable extent, winging it from the desperately dredged-up roughly-four-decades-old recollections thereof.