Mathematicians

[flymo]

Originally Posted by EssexDave

...stuff...

+1

There are actually a number of things in the 11 plus (depending on which particular subjects it includes) that are not taught in the syllabus for this age group. Some of it does indeed test ability rather than what you've been taught. Practice and teaching can to some extent narrow the gap between ability ranges.

Key point though is that these mathematical expressions are only ambiguous if the rules are not fully understood.

i just just voted and more people say 5 then 7!!!

the question was for people who do maths (mathematicians). if a mathematician had put 5, they should be shot for getting this basic concept wrong!!!!

[Sid Squid]

Originally Posted by mikerj

Exactly this. I'm quite stunned at how few people in the thread know this, is it not taught any more?

Not quite:

Originally Posted by Sid Squid

The question as it is written

I wrote that quite deliberately, precisely meaning that the question is posed to those who will almost certainly be unaware of such things, thus the ambiguities of the notation are in this circumstance particularly amplified.

I commonly use equations such as this in my work, and I always follow the teaching of my secondary school maths master; make it plain. Thus the question, as it is written and for whom it is written should not be imprecise, Mr Kaye would brook no argument on this subject, operator order should not be relied upon in common equations as it can be ambiguous, if you wish the question to be asked in a given manner phrase it so.

He had a particular bee in his bonnet abut this, (and many other mathematical things too), this has stayed with me, and the things I write at work are very rarely misunderstood, and if they are it isn't because of the notation.

Make it plain: The answer to the OP's question, as it is written is 5.

[flymo]

Originally Posted by Sid Squid

[...]The answer to the OP's question, as it is written is 5.

I disagree, just as my calculator disagrees. Your maths teacher is probably correct in that expressions can be made more easily understood by adding brackets as necessary to avoid confusion. But maths is maths, the rules aren't optional just because they are misunderstood.

1 + 2 wouldn't be equal to 5 if I didn't know how to carry out addition.

Originally Posted by flymo

I disagree, just as my calculator disagrees. Your maths teacher is probably correct in that expressions can be made more easily understood by adding brackets as necessary to avoid confusion. But maths is maths, the rules aren't optional just because they are misunderstood.

1 + 2 wouldn't be equal to 5 if I didn't know how to carry out addition.

Exactly this.

Ignorance does not make an answer correct if it is in fact incorrect.

I agree that on occasion, putting brackets in may well simplify things for those that do not understand operator precedence. However, this was drummed into me in year 5 & 6 (year 6 being the 11+ year).

By not putting the brackets in, they are not testing whether you can do 7-3, or 6/2 - they are testing whether they know operator precedence.

[MisterTommyH]

Originally Posted by Sid Squid

if you wish the question to be asked in a given manner phrase it so.

He had a particular bee in his bonnet abut this, (and many other mathematical things too), this has stayed with me, and the things I write at work are very rarely misunderstood, and if they are it isn't because of the notation.

Make it plain: The answer to the OP's question, as it is written is 5.

I agree, and often put additional brackets in where they are not needed for clarity - there is nothing wrong with this, however the answer to the question as it is written is 7. The fact that brackets would make it easier, or that the user doesn't know the correct order of operations no more makes the answer 5 than it does cheese.

The question appeared in an 11+ practice and is therefore there to test if the pupil knows the correct order without the brackets. If the brackets were there, the question would have no point.

I can understand why people say 5, and have done the same myself at times, but it is not, and will never be, the right answer.

If you asked someone in chemistry what water was made of, perhaps at 11 you would accept 'hydrogen and oxygen' as a correct answer.......you would not, however, tell someone who put '2 hydrogen atoms and 1 oxygen atom' that they were wrong. That is effectivly what this question does.

[Sid Squid]

I'd like to agree, possibly because I was taught the notational differences, but I can't because of the difficulties that they cause.
This isn't changng the rules - this is making it plain for everyone with plain notation that more people more likely already know.

The simple fact that opinion is split strongly suggests that many are not aware of the differences, a simple and plain use of the brackets just about all of us are already familiar with removes ambiguity, I don't think anyone has added up or divided incorrectly, simply the phrasing of the question is far from plain for many people. Add to this, (see what I did there? ), the fact that some of the people I work with are not aware of the difference, (and these are not uneducated people, they are people with professional electrical and electronic qualifications, so I suspect this also means a significant chunk of the population), and it further suggests that simplification of notation and attention to phrasing is the best way.

There's no change in the maths - it's just making more people understand the question.

[pookie]

I think most are forgetting the context of the mathematical question and the aim of the test. It is for 11+ and should be treated as such. I'm sure in the eyes of the examiner there is one answer and marked accordingly irrespective of whether some might consider the question is plain, simple or ambiguous.

Maybe those 11+ candidates will become engineers and educated people that one day change the questions in the future.

[flymo]

Originally Posted by Sid Squid

I'd like to agree, possibly because I was taught the notational differences, but I can't because of the difficulties that they cause.
This isn't changng the rules - this is making it plain for everyone with plain notation that more people more likely already know.

The simple fact that opinion is split strongly suggests that many are not aware of the differences, a simple and plain use of the brackets just about all of us are already familiar with removes ambiguity, I don't think anyone has added up or divided incorrectly, simply the phrasing of the question is far from plain for many people. Add to this, (see what I did there? ), the fact that some of the people I work with are not aware of the difference, (and these are not uneducated people, they are people with professional electrical and electronic qualifications, so I suspect this also means a significant chunk of the population), and it further suggests that simplification of notation and attention to phrasing is the best way.

There's no change in the maths - it's just making more people understand the question.

Now that I agree with totally. What I don't agree with is the answer of 5 mentioned earlier. So, as the question was written it could potentially lead to the incorrect answer and could be avoided by adding brackets or re-phrasing the expression but under no circumstances can the answer be correctly 5 as it is currently written.

[MisterTommyH]

Exactly, so in the eye if the marker, the kid who actually knows the rules (which some at 11 will) becomes wrong and loses the mark.

While it may be simple to him, an examiner should never allow something like this to detract from someone who actually knows more. If it was a GCSE or an A level exam people would be calling for the examiners head...