Primary maths help please

[isitwineoclockyet]

My daughter's homework was all about odd & even numbers, & whether adding & subtracting odd & even will give you an odd or an even answer. So for example, odd + odd = even.

All very straight forward, except that some of the sums had decimals in them (31.3 + 42.6, for example)

DD couldn't do those & asked for our help. DH & I both thought the concept of odd & even only applied to whole numbers, except in certain specific cases, which neither of us can remember but which we thought were probably beyond the scope of the average primary maths lesson.

We asked our yr 9 daughter what she thought & she said she also thought odd & even only applied to whole numbers & asked whether they were supposed to round them.

I've just been & asked the school, & their answer is that if it ends in 1, 3, 5, 7 or 9 then it's odd, regardless of how many places beyond a decimal point the last digit is (so 3 is odd, 0.3 is odd, & so is 0.03.

Can anyone with a maths background confirm for me who is right?

(I should say there is some history here, including previous homework which had a 5x3 grid on it, & the statement underneath "In the 16 squares above.....")

Thanks.

But I will stop doing pointless calculations now!

isitwineoclock you and me both, then, taking our children's education into our own hands...:)

I have entered this forum just because I am shocked about this story, and would like to help.

There is absolutely no doubt here: the concept of odd and even numbers only applies to whole numbers, to integers. There is no question about it.

A number with a fractional part, i.e. with something other than 0 to the right side of the comma, is not an integer, and cannot be even or odd.

Worse than that: many fractional numbers don't even have a "last digit". Take the fraction 100/99, for instance, it is 1.010101... There is no "last digit".

I think the problem is the teacher may be thinking a "decimal number" might mean a number with fractional "decimal places", and not an integer written out in the "decimal base". In other words, the teacher thinks the word "decimal" is synonymous to fractional.

What exactly is the subject being taught, is it odd/even, or is it numeral systems? It only makes sense to talk about the relation of the last digit to parity when teaching numeral systems... I think this is probably what is happening, and the teacher is thinking "decimal numbers" mean fractional numbers, with "decimal places", and not an integer written in base 10.

Anyway, the teacher is plain wrong and you are right. Do not hesitate. Tell your kids THIS IS THE FACT, and let the teacher lose credibility. It's not our problem, for crying out loud... Nothing pisses me off more than a math-murderer.

If what's required is a good authority for the explanation of why this teacher is wrong, might I recommend Mathworld (the web's most extensive mathematics resource):

mathworld.wolfram.com/EvenNumber.html

Good luck.

Unbelievable! How does this person get to teach anyone maths???

I have just been practising the QTS maths skills tests for my test tomorrow and I'm not even going to be a maths teacher and I know this is wrong!

LOL @ spongebob "sprinkles of wrongness".

I love maths me, and people getting it wrong make me sad. Teachers teaching it wrong make me angry

Odds and evens only apply to integers (only whole numbers can be odd or even). Absolutely shocking that the teacher doesn't know this, please correct him and point out his lack of basic mathematical skills to the head. This person should stay away from teaching maths.

Why can't you take this to the head, OP? It's their duty to deal with your complaint.

Please please print out the wikipedia and wolfram (and any other!) references here and print a letter to go on top of them to point out that, as you had pointed out, odd and even numbers can only ever be integers, as these online references state. Also that just in case there was a chance these might be wrong, you checked with some MN friends who are highly qualified in Maths and include lecturers and teachers in Maths, people with higher degrees in Maths (and the MN massive) there is not a single one of them who has ever heard of odd and even being applied to anything other than integers.

I'd also include the bit where you suggest that the teacher is getting confused by decimal numbers and decimal places as xor0 puts so well to make it clear that you understand not only about odd and even numbers but where this teacher is going so wrong.

Copy this letter to the maths teacher, the form teacher (if different, got a bit sidetracked on that one sorry), the head of maths for the school (if it is somebody different from these people) and the head teacher.

It is such a basic principle to be getting wrong and is being taught so badly that it really needs to be stopped before it can be started!

And teach your dd to write/say 'trick question - not integers' as an answer to anything that involves decimals...

The OU guide with the maths course I've just finished defines odd thus: An odd integer is one that is not divisible by 2.

Its definition for even is thus: An even integer is one that is divisible by 2.

In the basic course book itself it says: Each natural number is either even or odd. The even natural numbers are those that can be divided by exactly; that is, an even number can be divided 'evenly' into two parts.

So you have a definition from the OU as well as Wiki and Wolfram. I am not at all astonished that this teacher has got it wrong. My dd's first primary teacher made very similar mistakes (in all subjects). He was a complete idiot and I've no idea how he got his qualification. Luckily, her next teacher was excellent.

Thanks for all your comments.

I suspect Xor0 is absolutely right & he's got confused by the whole decimal number thing. I had a wobble over it yesterday before pulling some long-forgotten maths from the back of my brain.

He's told the class he's going to "go over it again for the benefit of those who were confused", & this is his last chance to get it right. Perhaps he Googled it overnight & he'll come back & say you can't classify fractions as odd or even?

Not sure what my next step will be if he repeats what he said before. He was not remotely open to discussing it yesterday. He basically smirked at me, told me I'd obviously not encountered sophisticated enough maths & told me to go. I've checked with my DD & he is her maths teacher, and her form teacher, and the maths co ordinator, so I don't have too many options there!

For those who asked about the head teacher, if I went into detail about why I can't speak to the head, you'd think I was making it up. He's not very approachable. I could contact the chair of governors but my DH thinks that would be an OTT approach to what is just a silly mistake on a tiny part of the maths curriculum. My main concern about speaking to her is that she won't give two shiny shits. She talks a good talk, but I think she's as intimidated by the head as the rest of us.

I did mention it to some of the other parents in the hope that they'll raise it with the school, but most of them will know better than to even try.

So many of my friends have said "You've reminded me why I always hated maths", & this is partly what pisses me off so much about it. My DD was perfectly comfortable with her own initial conclusion that it couldn't be done. Now she thinks it's terribly complicated, & if her teacher & her parents can't agree on it then she can't hope to understand it.

Never mind the head or the chair of governors - I feel like writing to Michael Gove!

Perhaps you should. Universities have problems enrolling students to do maths degrees and part of that might be that such a lovely subject is mystified by morons at primary age. Once children feel that it is too complex they lose interest.

I lost my way with maths at matrices and with the benefit of hindsight, I realise it was hard because the teacher didn't really get it either. You can only teach something well and simply if you understand it thoroughly. The very fact he has to go over it again means it was not well taught in the first place and his confusion showed to the students.

I'm not sure I would let this go. The teacher is wrong - that in itself is not terrible, teacher's are wrong sometimes. However, the teacher will not admit the possibility he is wrong and that is a real problem.

Write out the letter as suggested above with all the online references and send it to the teacher in question with a polite note that if he fails to answer your queries clearly without resorting to any patronising head-patting of the 'your simple little mind wouldn;t understand this primary level maths' type then you will be sending the query to the papers to see if the general public have better luck with it.

I'm sure he'll be mortified thrilled to have his incompetence brilliant understanding of maths exposed in the press...

I don't think Wiki would help you, because it says:

"A number (i.e., integer) expressed in the decimal numeral system is even or odd according to whether its last digit is even or odd. That is, if the last digit is 1, 3, 5, 7, or 9, then it's odd; otherwise it's even. The same idea will work using any even base. In particular, a number expressed in the binary numeral system is odd if its last digit is 1 and even if its last digit is 0. In an odd base, the number is even according to the sum of its digits ? it is even if and only if the sum of its digits is even." [http://en.wikipedia.org/wiki/Parity_%28mathematics%29 Reference]]

Which is what the teacher is claiming.

Yes but even going by what Wiki says, you could take any so-called "odd" decimal number such as 4.3 and turn it into an even number by the addition of a totally meaningless string of zeros. 4.3000000000000 has the same value as 4.3 and a teacher who doesn't understand this is quite a worry as they are also supposed to be teaching place value.

xor0 covered this up-thread somewhere -

"I think the problem is the teacher may be thinking a "decimal number" might mean a number with fractional "decimal places", and not an integer written out in the "decimal base". In other words, the teacher thinks the word "decimal" is synonymous to fractional."

I didn't get this the first time i read the wiki link, but I do now (well enough to explain to the teacher why he's misunderstood it!). Initially I did wonder whether he had actually written that himself though

Perhaps the teacher contributed the WIKI information

sorry crossed post

It isn't a tiny part of the maths ciricuculum though is it. It is a fundamental error probably based round a too hasty ready of a wiki entry. I would be worried on two counts, first that he made the mistake in the first place and second that he is not prepared to admit that he was wrong. Given the cr**P teaching of maths in schools it is not surprising that many primary school teachers do not have the basic skills but those with weak maths should be supported and not left to confuse future generations of teachers because if so the problem will go on and on and on

go to the governers and the press

I was thinking about this in the bath last night. You could turn it into a sort of project for a mathematically minded child. The definition of "odd" and "even" the teacher is using is obviously flawed, as it produces mathematical contradictions. So your daughter can produce a formal mathematical proof that the definition is incorrect.

You could come up with a whole new definition of "odd" and "even" and a whole new set of rules to cover what this guy means.

Definition
Let us define a rational number (expressed as a decimal) to be "k-odd" if the k-th digit after the decimal point is an odd integer, and the n-th digit after the decimal point is zero for all n greater than k. Similarly, a rational number is "k-even" if the k-th digit after the decimal point is an even integer and the n-th digit after the decimal point is zero for all n greater than k.

We can come up with a new set of rules for these numbers defined as above.

Then the sum of two k-odd numbers would be k-even;
The sum of a k-odd number and a k-even number would be k-odd;
The sum of two k-even numbers would be k-even.

Although the sum of two k-odd numbers would be k-even, it may not be (k-1)-even (which explains the flaw in the teacher's definition). Similarly, it is possible to find examples of sums of k-even numbers which are (k-1)-odd and a pair of k-even and k-odd numbers which are (k-1)-even.

I would explain it to the teacher like this if he was supposed to be qualified in maths :o I might inprecede it with a proof from basics that the sum of two odd numbers is odd etc if I really wanted to put him back in his box.

Is there another nice teacher at the school that you could talk to 'for advice on how to get through to the teacher'? Hopefully when you explain the problem they will be so horrified that they will sort it out for you.

Failing that, I'd send a nice letter to ofsted and copy it to the teacher and the head asking if they could clarify that odd and even numbers do have to be integers as idiot teacher seems to think the rest of the world has got it wrong.

I'd also get MNetters to help you write a good letter to the times educational supplement (or any other educational paper, sorry not a teacher so not sure what they are) asking how many other teachers out there are teaching this and what should you do as a parent when your child is obviously being taught wrongly!

Interesting topic. I can see why everyone is annoyed. Taking the positive. Your child will learn heaps from this situation more than just what odd and even numbers are. Good luck. I used to love maths because I thought it was black and white (lol). Shame I can't remember any of it!!!

howto I fear that positives and negatives are going to be a whole different kettle of fish when this teacher gets hold of them if he can screw up something as clearcut and straightforward as odd and even!!

OP what an utterly frustrating situation for you. If the teacher / maths coordinator can be so misguided about this, what else is he getting wrong?? Please don't leave it here if you possibly can - horrid that the head and governors are such hard work / helpless though.

How about writing a letter to the head outlining concerns that the teacher is so reluctant to discuss with and explain something to you, and to concede that he might be wrong. (Outline the actual maths issue in an attachment rather than getting everyone bogged down in the details of the numbers.) Copy to any or all of: teacher in question, all governors (not just head), your local councillor, chair of the LA education committee and whichever official is in charge of education at the LA.

The point is the school is putting up a brick wall against you whilst teaching utterly flawed basic principles to its pupils. This would point to them having very few quality control checks in place, governing body being ineffective etc. These are the points the school, governors and ultimately LA need to address. You don't actually need them to ponder the issue of integers and fractions.

Of course all this marks you out as the "parent-who-causes-trouble" ...

I'm very much liking k-odd and k-even numbers! I wonder if my older children are good enough at maths to follow this? We could indeed turn this into a much broader learning opportunity for the whole family :)

destination I am already "parent who causes trouble", unfortunately. I never intended to be, as both my mum and my MIL were primary school teachers & I imagined myself as one of those enthusiastic, supportive parents who went on trips & helped out at the fete. Your last paragraph unfortunately sums up the situation at the school far more concisely than I would have managed to do.

I know that theoretically there is a process for making complaints (head, governors, LEA), but in my experience, if the head just stonewalls everyone, there's little point in pushing it (I got as far as the CoG. When she was all nice words & no action, I called the LEA & was told there was nothing more I could do other than trying to talk to the head again)

On the plus side, one of my DDs has said she will write to Michael Gove when she gets in tonight!