[Closed] What was the simon mayo maths question last night?

6 - 5 x 0 plus 2 divided by 2

[s]So 4 then, well the way it's written there is anyway.[/s]

Edit Arse, 7.

7?

6 minus 5 is 1
times 0 is 0
plus 2 is 2
divided by 2 is 1
This is the answer most people incorrectly get

My wife and son both say the answer is obviously 0 ❓
I didn't hear tonights show to find out the correct answer and I'm obviously not Carol blinking Vordermen

1?

edit - oops

7

do the multipy/ divide bits first then the +/- bits.

i struggled to figure out any way of making 4 though 😉

6-(5x0)+(2/2)

With no parentheses the answer is 7.

6 - 5 x 0 + 2 / 2 becomes
6 - 0 + 1 as you do the multiplication and division first
7

Edit the 4 is from (6+5x0+2)/2. It's been a long day but I'm glad that we QA here!

It's done right to left.

2/2 = 1

5x0 = 0

6+0+1 = 7

Think that's right I'm still in shock Simon Mayo is still working.

What is this, facebook?

BODMAS

So the question is "do you understand operator precedence", and the answer is often "no" because people of a certain age (well represented in Radio 2's audience I expect) grew up using basic calculators that calculated a result every time you pressed an operator key. So eg, 1 + 2 * 3 would give 9 rather than 6.

If the question was 'Have you heard of operator precedence' the answer would still be 'no'.

or 7, Cougar 😉

Well done, you spotted my deliberate mistake! 😳

Should still be clear what I meant, anyway.

I'm guessing this is the maths equivalent of grammar pedantry.

and just as funny

Operator what?

Apostrophes are pointless. Maths is ace. innit

I'm guessing this is the maths equivalent of grammar pedantry.

Not really as the rules of grammar are arbitrary, the rules of Maths aren't.

I'm guessing this is the maths equivalent of grammar pedantry

Not really, there's only one right way to do it.

It's embarrassing as a nation that so few people get this right. It's nothing to do with how calculators work; it's more to do with a fundamentally poor understanding of the subject. What's worse is that an inability to do basic maths is almost something to be proud of - "I'm rubbish at maths, me...". Well, you wouldn't be proud of not being able to read and this is exactly the same thing.

It's ironic that most of the people who get this wrong are the same ones who bemoan the passing of the O-Level. Yeah, sure, proper thickies will never get the grasp of it but I should think most 11 year olds will get the right answer.

BODMAS/BIDMAS was drummed into us for far too many years at school. Far more than a lot of the basic grammar rules if I remember rightly (that makes me sound really old, school wasn't all that long ago!).

Oh the rules of maths are arbitary in the sense used here and there is only one agreed way to do it but it is no more true than the ruls of chess or the highway code it is just what we do.

Unless of course you can prove the axioms of maths are true , which of course, due to Goddelisation* we know cannot be done 😉

Cant do maths as well as I can do philosophy

For example in Euclidean geometry parallel lines dont ever meet- arbitary rule taken to be true. so within this geometry this rule is true as it is built on this assumption[axiom]. however with non euclidean geometry they can touch and this is what the universe is made of.

We could change the order of how we do operator precedence, I assume as it is not exactly mirroring nature] the only thing we need is that we all agree in what order we do it to get the "right answer"- ie agree the rules
Those who get 7 are correct if you use a different precedence.
I dont know enough about maths to know how they decide what was the right order- does anyone know or is it just the rules /arbitary?

* http://en.wikipedia.org/wiki/G%C3%B6de l's_incompleteness_theorems

Obviously, if we didn't have maths the world would continue to turn. But the only way to unambiguously communicate a mathematical idea is to use the BODMAS convention.

In languages you can get the grammar completely wrong and still get the point across - as we've just seen it only takes a small change on a simple function and the whole thing falls apart in maths.

So, yes, you could have a different convention but you'd have to define it in advance.

The rule of Maths aren't arbitrary. Suppose you had a single five pound note in your pocket. That can be expressed in terms of paper money like so

5*1+10*0+20*0+50*0

If you do that sum simply the way it is written then you will come to the conclusion that you have no money as the answer is zero. Just because the axioms of Maths haven't been proven correct doesn't make them wrong.

Invoking Goddel doesn't actually help your argument.

In languages you can get the grammar completely wrong and still get the point across

Agreed. I usually understand what JY is trying to say. (sorry)

[url= http://singletrackworld.com/forum/topic/22222222222222-22-x-0 ]This all sounds strangely familiar[/url] 😉

Goedel's incompleteness theorem is about the incompleteness of formal logic: in a formal logical system there are always statements which are true, but cannot be proven (unlike axioms, which are considered to be axiomatically true). [/pedantry]

These type of maths problems are complete BS in my opinion: it would be obvious to anybody written down, but people interpret them differently verbally.

I dont know enough about maths to know how they decide what was the right order- does anyone know or is it just the rules /arbitary?

y = ax^2 + bx + c

everyone knows what that means and it follows the conventions. But if there was no convention, or the convention was do add/subtract before multiplication etc then you would need to write that as:

y = ((ax)^2) + (bx) + c

which is obviously not so tidy.

^^^^ Thanks for that.

Agreed. I usually understand what JY is trying to say. (sorry)

Flounces

TBH it is a mixture of not caring, not trying and bad typing.
It would take startling levels of unawareness to realise I dont punctuate or spell accurately on here. { had to resist adding commas' then so I added a pointless ']

Just because the axioms of Maths haven't been proven correct doesn't make them wrong.

Invoking Goddel doesn't actually help your argument.

Goedel's incompleteness theorem is about the incompleteness of formal logic:

in a formal logical system there are always statements which are true, but cannot be proven

(unlike axioms, which are considered to be axiomatically true).

paulosoxo - Member
BODMAS

How about: it is [i]true[/i] because if you type that sum into any decent calculator or maths program, or ask anyone with any interest in maths, you will get the answer 7.

Yes it [i]is[/i] a "convention", but the so is drawing a straight upright line with a hat on to represent a single unit.

For clarity we should really use [url= http://en.wikipedia.org/wiki/Reverse_Polish_notation ]reverse polish notation[/url] which by my reckoning gives us:

[b]6 5 0 x - 2 2 / +[/b]

Much easier 😀

For clarity we should really use reverse polish notation

At college, we used to refer to that as Egdelp.

Been a while since I studied the first incompleteness theorem, but as I understand it:

A "formal language", or "logical system" consists of:

- An algebra: i.e. operators with predefined meaning (addition, multiplication etc).
- A set of axiomatic statements which must be self consistent (i.e. no contradictions), and not derivable from the other axioms.

Statements are then made which are consistent with the algebra, and may be shown to be consistent with the axioms (true) or in contradiction (false). There are also statements which may be made that may not be proven or disproven (e.g., if one axiom is removed and treated as a statement, it cannot be proven or disproven).

Therefore if we find a statement which is true and cannot be proven, we can simply make it an axiom.

Goedel's first incompleteness theorem states that there are true statements which cannot be proven in any system with a finite set of axioms.

The proof is one of the best, counterintuitive and horrifically complicated bits of maths I've ever come across. It involves metamathematics and Peano arithmetic and amazingly is published entirely on wikipedia [url= http://en.wikipedia.org/wiki/Original_proof_of_G%C3%B6del%27s_completeness_theorem ]here[/url].

gonefishin - Member
I'm guessing this is the maths equivalent of grammar pedantry.
Not really as the rules of grammar are arbitrary, the rules of Maths aren't.

The order of operation has nothing to do with the rules of mathematics. It is just convention, like grammar.

To suggest that it is anything otherwise is frankly ridiculous.
Plus, writing equations without parentheses is like writing a sentence without punctuation - laziness that leaves the statement open to interpretation.

At college, we used to refer to that as Egdelp.

I like that 😀

The order of operation has nothing to do with the rules of mathematics.

[url= http://www.bbc.co.uk/schools/gcsebitesize/maths/number/orderoperationrev1.shtml ]Odd that they teach that rule at GCSE level then. [/url]

writing equations without parentheses is like writing a sentence without punctuation - laziness that leaves the statement open to interpretation.

y = mx + c

An equation familar to anyone who has done GSCE maths. Where are the brackets?

Epistemology!

I've only had 2 glasses.

Ah BIDMAS I forgot about that, guess I was just lucky and remembered enough to get the answer.

The order of operation has nothing to do with the rules of mathematics. It is just convention, like grammar.

To suggest that it is anything otherwise is frankly ridiculous

No its not, it's the only way to get the correct answer. Have a look at my first example for evidnce of that or think about this. If you have three bags with two apples and two bags with five apples the total number of apples could be written like.

T=3x2+5x2 which if you were to ignore operator precendence would give the answer 22.

Or you could write it equally correctly as

T=3x2+2x5 which would give 40

Or

T=2x5+3x2 which would be 26

Or

T=2x5+2x3 which would give 36

Where as the correct answer is 16.

Operator precendence isn't a "convention" it is the [b]only[/b] way to get the correct answer. To say otherwise means that your grasp of maths is about the level of a primary school child.

Very well explained gonefishin,

I mean, really well explained, top mark, head of the class etc

Is it obvious that my mother was a Maths teacher? 😉

to be specific, while the order of operation is absolute, the notation by which it is relayed is convention. there are a number of notation systems: PN and RPN for example