Can't do my 9 yr olds maths homework! Help!

[Solo2]

I got a 'C' at Maths O level, 32 yrs ago and haven't done any maths since - except the usual stuff you do as an adult - with a calculator!

My 9 yr old twins have lots of Maths homework to do these hols and because of being away and then currently all v sick, haven't had time to tackle it. We tried some this morning, before DT1 vomited yet again - having had 10 days of sickness now - but, I hasten to add, not brought on by the maths!

I think I'd nowadays be called dyscalculic but I also think the homework may be pretty hard anyway. So I need some help. Here are some examples:

"(xx) squared = 79xx What is x?"
"(aa)cubed = 10388 What is a?"
"yy multiplied by 5y = 3942 What is y"
"mmm multiplied by mm = 43956 What is m if it's the same digit throughout?

Can anyone first tell me the answers and secondly, help me to explain in a crystal clear, easy way to two 9 yr old boys - who are in Yr 5 middle set for Maths - HOW to start tackling these?

Apparently, they haven't done anything as hard as this at school so far. I vaguely remember there's a way to tackle these but believe I did this kind of sum at age 14 of so, not at age 9 - or am I just so crap at Maths?

Algebra at age 9? Now, I did GCSE maths last year, but it would take me some time to work those out. I'd leave them.

omg! I haven't got a clue.

DS1 is in the midle for maths (also YR5) and I can guarantee he would look at me like

\link{http://www.google.co.uk/imgres?imgurl=blog.otterbox.com/wp-content/uploads/2010/09/confused-cartoon-face.jpg&imgrefurl=blog.otterbox.com/2010/09/&usg=__cwcO0HhNN0WTA9IMHS0DpMQScGY=&h=318&w=341&sz=17&hl=en&start=0&sig2=GWyRUsnqRd1sKLr7YY-T_Q&zoom=1&tbnid=WxGQ21ISaDbw7M:&tbnh=150&tbnw=161&ei=eZYgTfGkLImLhQeMuYy4Dg&prev=/images%3Fq%3Dconfused%2Bface%26um%3D1%26hl%3Den%26biw%3D1366%26bih%3D643%26tbs%3Disch:1&um=1&itbs=1&iact=hc&vpx=653&vpy=336&dur=2549&hovh=217&hovw=232&tx=114&ty=156&oei=eZYgTfGkLImLhQeMuYy4Dg&esq=1&page=1&ndsp=21&ved=1t:429,r:17,s:0\this}

the last one is m =6
ii my doing the inverse(opposite) ie 43956 divided by (then I tried 11, 22, 33, 44 etc until got to 66

I think rewrite it into a way you can understand

1. divide through by xx

so xx= 79 x is square root 79 (don't have calcultor)

1. (aa)cubed also means aa(to power of 6)

so a is the sixth root of 10388

1. Means same as y squared times 5 y, so 5 y cubed, so y is the cube root of (3942/5)

1. m (to power of 5) is 43596

So m is the fifth root of 43596

1. Sorry should be a (to power of 6)

Gawd I hope I'm right

If this is the nature of the questions I would ask for better written questions tbh

"(xx) squared = 79xx What is x?"

a sqaure number is a number multiplied by itself - eg 4^2 is 4 x 4 = 16.

So what number multiplied by itself is 79??
could be 7921 which is 89 x 89

a cubed number is multiplied by itself 3 times - eg 4 x 4 x 4 = 64

not sure how they are supposed to do it - maybe by trial and error - eg try 15 x 15 x15 and see what you get and decide whether you need to go up or down from that.

yy x 5y = 5y^3 (5 times y cubed) - so you need to divide by 5 and then find the cube root.

mmm by mm would be m^5 (5 times itself).

I am not sure I have read what you have written properly because those sums don't come out as whole numbers and seem quite complicated for a 9 year old (mine certainly couldn't do them, although he does understand what square and cube numbers are).

Have a chat with them and see if they can find anything familiar in the questions - they idea of homework is supposed to reinforce what they have done at school.

to be honest - if they are the actual questions they look like bloody silly ones ! Certainly not a standard way of writing maths (maybe the modern primary way of doing it but not the way any grown up except a primary teacher would recognise !!).

I'd have assumed the same as maryz, that aa meant the same digit repeated e.g. 11 or 22 or 33.

If it just represents a 2-digit number then I would use trial and improvement.

So for the first one:

"(xx) squared = 79xx

80x80= 6400
90x90= 8100

Try something in between:

85x85= 7225

Bit bigger:
86x86= 7396
89x89= 7921

I'd use the same method for the others, start with a fairly random number and gradually get closer.

I would guess that the teacher is trying to test their problem solving skills more than algebra. There is a lot more emphasis these days on solving these kind of problems and explaining your reasoning.

Not this primary teacher ( and I'm a yr 6 maths specialist!) If the same letter is being used, it SHOULD represent the same numeral, ( so xx should be 22 or 33 or 44 etc rather than eg 27 ) and these are FAR to complicated as they are written for yr 5 mid set!

And I would agree with pozzled, if the letters represent just any number then I would sugest trial and error too!
An example of badly thought out homework I'm afraid!

You can't use xx to represent missing digits when you've already used x in another context in the same equation!

So to my mind the first one is (x2)2 = 79x^2
so x is the sqrt of 79

But agree those questions are dreadful - is the first one really written exactly like that?

Ah I see
So if that's the case, xx has to be a digit, which, when squared, ends in itself

anything ending in 1^2 ends in 1
anything ending in 2^2 ends in 4
3-->9
4-->6
5-->5
6-->6
7-->9
8-->4
9-->1

so it has to be 11, 55 or 66
which is isn't :o

One of the most basic rules of algebraic notation is that xx = x^2
They are setting the children up for major confusion and I would be furious if my children were expected to work with this! Seriously, don't let it drop - I'd be tempted to bring it to the attention of the local authority.

Well, at least I'm not just stupid then! It looks as if these really are tricky for 9 yr olds. Just trying to think about how to do them gets me in a sweat! I wrote down the second one incorrectly, BTW. It should have been "(xx) cubed = 103 823. What is x?" Otherwise, all the others are as the sheet says.

My twins have no idea how to tackle them and of course it also then involves a lot of trying multiplication etc. I've read the blurb at the front.

The focus is on solving problems, recognising patterns, generalising and predicting, ending with, "Children should increasingly be able to extend the ideas of a particular problem by adding their own ideas. They should not think of these problems as closed (ie with only one possible answer) but should be prepared to spend time on each one, developing possibilities within it".

There are 16 pages of problems like this and different ones, including creating Binary trees, making different Pentominoes doing, "The Sieve of Eratosthenes". None of this is familiar to me at all! I have no idea how they'll get it all done, as they only have 3 days left now and are v sick and haven't bene able to do much before this because we were away and then all sick from Xmas day.

What level of Maths is this? They haven't, to my knowledge, done anything so complicated at school. They've done sums with missing numbers in them lots before but nothing as hard as this with squared and cubed numbers but this feels like stuff I did at 14/15/16!

PS They're at a fee paying academically selective school - so can't complain to the LEA.

In the top Maths set, they freqently have children who win some of the UK national Maths competitions. So I know they're all working beyond the usual Yr 5 level but I thought it was one yr ahead and my twins aren't particularly good at Maths for children at that school and I'm a complete dunce at Maths! I'm sure this has to be more than Yr 6 level but perhaps not?

God, I thought I was good at MAths before I read that! (I was, 2 O levels and 2 A levels but it was a while ago)

THe whole thing as you've written it looks like a pile o'shite for a 9yo level - I'd be writing a stiff letter to whoever set them, explaining that your twins have not been adequately taught the skills required for the problems as mindreading doesn't appear to be on the syllabus and that appears to be necessary to understand what the teacher actually wants from the pupils!

Very confusing way to write any maths problem, especially (as others have said), using double letters at this stage when it's going to mean something (possibly) entirely different later.

They should not think of these problems as closed (ie with only one possible answer) but should be prepared to spend time on each one, developing possibilities within it"

that is bloody stupid !! There is one possible answer with maths - the right one ! (well maybe two if you consider negative roots as well). What there is is numerous methods of getting to that right answer - which is maybe what they are getting at - ie thinking your way around a problem. A good aspiration but no bloody use if it is not clear where you are trying to get to.

As someone else said xx should mean x2, so (xx) cubed (which you would never write in maths) would be the cube of x2, which would be x^6 - which is certain;y far beyond the average 9 year old. Which means they are not using mathematical notation correctly.

I would be very unhappy with that and complain to the school. What the hell point is there in teaching them notation that is just plain wrong that they have to unlearn at a later stage ?!

Sorry - pet hate here.

For me it's not so much the level of them but the ambiguous way they are set out - xx is x^2, everyone agrees! And yet in this homework they are used in a different way