Can you do an 11 year olds Maths homework?

Gizmodo

This is from my 11 year old Neice's practice Maths test. In the actual test you get 3 minutes per question.

3 different numbers a b and c. 
a+b+c=100
the mean of a&b  = 40
the mean of b&c  = 35
what are  a b & c

cornerblock

Can you repeat the question?

scwxx77

c = 20
b = 50
a= 30

Tom Butcher

Yes I did it but difficult for an 11 year old I'd have thought - depends if they see the first two must equal 80 so c must be 20 I suppose - see that and it's easy but how many 11 year olds would - probably not many.

cornerblock

scwxx77 wrote:

c = 20
b = 50
a= 30

+1 :?

MattC59

yes.......... even after the thick end of a bottle of Rioja

ddraver

I needed Tom's hint, but I got there with some pen and paper :oops:

Geology is the non-mathmetical science (thank god!)

MattC59

ddraver wrote:

I needed Tom's hint, but I got there with some pen and paper :oops:

Geology is the non-mathmetical science (thank god!)

But what if someone asks how many rocks you've got in your bucket ?

DaveRobinette

took a while of thinking about it in my head and i'm doing A level maths :L
pretty sure we didn't have stuff like that when i was 11

+1 for geology though

MattC59

DaveRobinette wrote:

took a while of thinking about it in my head and i'm doing A level maths :L
pretty sure we didn't have stuff like that when i was 11

+1 for geology though

Geology ? Get yer ar*e into quantum physics !!!!!

jim453

MattC59 wrote:

yes.......... even after the thick end of a bottle of Rioja

Well done Matt, you can answer an 11 year old's maths question. But, in the spirit (presumably) of the original post, could you have done this when you were eleven? This is an extremely challenging question. I would predict that less than half the members on here would be able to correctly answer this within the time. I can do it now but definitely would not have been able to do it when I was eleven.

Did she get it right?

ddraver

MattC59 wrote:

ddraver wrote:

I needed Tom's hint, but I got there with some pen and paper :oops:

Geology is the non-mathmetical science (thank god!)

But what if someone asks how many rocks you've got in your bucket ?

First Rule of Geology is never ever give a solid answer. There is a famous (but probably rubbish) story of an exasperated engineer at Shell (or wherever) sending an e-mail around the whole company asking for a one-armed geologist, because every time you ask a geologists opinion they say, "well on the one hand it could be...."

Tom Butcher

I messaged my daughter with it (well it's easier than walking up the stairs!) - she's 13 and top maths group - she couldn't do it - but then again she probably spent about 5 seconds on it before going back to facebook. Sort of thing I reckon she'd get but it'd take her quite a bit longer than 3 minutes.

I think it's a good question though - if a little hard - encourages kids to look at what information they have been given and think rather than something they have just memorised how to do. For an 11 year old it'd have to be the last question on the paper though - give them that early on and it'd really throw some which would be unfair at that age.

MattC59

jim453 wrote:

MattC59 wrote:

yes.......... even after the thick end of a bottle of Rioja

Well done Matt, you can answer an 11 year old's maths question. But, in the spirit (presumably) of the original post, could you have done this when you were eleven? This is an extremely challenging question. I would predict that less than half the members on here would be able to correctly answer this within the time. I can do it now but definitely would not have been able to do it when I was eleven.

Did she get it right?

That's a fair point Jim, I hadn't read it like that :oops: I was quite pleased, but as mentioned, I've had a glass or two !
It's not a challenging question though, if you've been taught the method, then it's quite easy. But I agree, at eleven I'd probably not have been able to answer it, but we weren't taught the method until a couple of years later.

jim453

MattC59 wrote:

jim453 wrote:

MattC59 wrote:

yes.......... even after the thick end of a bottle of Rioja

Well done Matt, you can answer an 11 year old's maths question. But, in the spirit (presumably) of the original post, could you have done this when you were eleven? This is an extremely challenging question. I would predict that less than half the members on here would be able to correctly answer this within the time. I can do it now but definitely would not have been able to do it when I was eleven.

Did she get it right?

That's a fair point Jim, I hadn't read it like that :oops: I was quite pleased, but as mentioned, I've had a glass or two !
It's not a challenging question though, if you've been taught the method, then it's quite easy. But I agree, at eleven I'd probably not have been able to answer it, but we weren't taught the method until a couple of years later.

What 'method' are you referring to that allows questions like this to be answered more easily? Many children who are comfortable with finding 'means' would not be able to do this. It is an extremely abstract question.

scwxx77

jim453 wrote:

What 'method' are you referring to that allows questions like this to be answered more easily? Many children who are comfortable with finding 'means' would not be able to do this. It is an extremely abstract question.

I agree it's maybe a bit of a stretch for an average 11 year old but it's hardly 'extremely abstract' and the method would be basic arithmetic.

MattC59

(A+B)/2 =40. We're told this.
Therefore A+B=40x2 = 80

A+B+C = 100
Therefore 80+C = 100
Therefore C = 20

(B+C)/2=35. We're told this.
Therefore B+20= 35x2 =70
Therefore B=50

As mentioned:
(A+B)/2 = 40
Therefore A+50 = 40x2 = 80
Therefore A = 80 -50 =30

A = 30
B = 50
C = 20

There's your method, it's very basic algebra. If you're comfortable with means, then one would assume that you're comfortable with basic algebra. If the question is being asked, I'm sure that the method is being taught, there's nothing abstract about it.

(No disrespect to your Neice Giz )

jim453

scwxx77 wrote:

jim453 wrote:

What 'method' are you referring to that allows questions like this to be answered more easily? Many children who are comfortable with finding 'means' would not be able to do this. It is an extremely abstract question.

I agree it's maybe a bit of a stretch for an average 11 year old but it's hardly 'extremely abstract' and the method would be basic arithmetic.

Algebra is abstract for an eleven year old. A question like this, which is essentially an arithmetic and means question framed in the language of algebra is extremely abstract for ninety five percent of eleven year olds (and many, many older children, and adults). As it happens, I have a degree in Mathematics, a Post Graduate Certificate in Education and twelve years experience of teaching Mathematics to 11-18 year olds.

Thanks to Matt for the very well articulated solution. I stand by my assertion that this is an extremely difficult question for an eleven year old. Some would be able to do it (very few) but most would not. If the girl in question managed to answer the question correctly then she deserves a very big 'well done'.

MattC59

jim453 wrote:

scwxx77 wrote:

jim453 wrote:

What 'method' are you referring to that allows questions like this to be answered more easily? Many children who are comfortable with finding 'means' would not be able to do this. It is an extremely abstract question.

I agree it's maybe a bit of a stretch for an average 11 year old but it's hardly 'extremely abstract' and the method would be basic arithmetic.

Algebra is abstract for an eleven year old. A question like this, which is essentially an arithmetic and means question framed in the language of algebra is extremely abstract for ninety five percent of eleven year olds (and many, many older children, and adults). As it happens, I have a degree in Mathematics, a Post Graduate Certificate in Education and twelve years experience of teaching Mathematics to 11-18 year olds.

Thanks to Matt for the very well articulated solution. I stand by my assertion that this is an extremely difficult question for an eleven year old. Some would be able to do it (very few) but most would not. If the girl in question managed to answer the question correctly then she deserves a very big 'well done'.

Good to see that we're not arguing for once Jim

finchy

I did

a + b = 80
b + c = 70

So, a + 2b + c = 150

This gives b as 50 then I did the rest from there. On a Friday evening. :roll:

straas

ddraver wrote:

I needed Tom's hint, but I got there with some pen and paper :oops:

Geology is the non-mathmetical science (thank god!)

I'd have to beg to differ on that one!

MattC59

johnfinch wrote:

I did

a + b = 80
b + c = 70

So, a + 2b + c = 150

This gives b as 50 then I did the rest from there. On a Friday evening. :roll:

Jim's gonna have fun with you John

finchy

MattC59 wrote:

johnfinch wrote:

I did

a + b = 80
b + c = 70

So, a + 2b + c = 150

This gives b as 50 then I did the rest from there. On a Friday evening. :roll:

Jim's gonna have fun with you John

That's OK, I'll just get this man onto him:

Gizmodo

No unfortunately Jim she couldn't work it out, but she did get the rest of the paper right though.
You're right Matt, it's knowing the method to work it out, that's what stumped her Dad who then emailed it to me!
I did it the same way as John (sorry Jim).

But at 11, not a chance, too busy out in the street on my bike to worry about algebra! :roll:

Keith47

I left school 34 years ago with, amongst other qualifications, only a grade "D" in Maths. When my daughter was 11 she came home with some maths homework, not unlike the one in the original post, and I was so embarrassed at my inability to help her that I enrolled at the local college on a GCSE Maths course which I eventually passed with a grade "A". Well chuffed with my little self as Maths had always been my worst subject. I still had to think long and hard about the OP's question though!

Cleat Eastwood

but if I had 5 oranges in one hand and 6 oranges in the other what would I have.....bighands, heha

nevman

johnfinch wrote:

I did

a + b = 80
b + c = 70

So, a + 2b + c = 150

This gives b as 50 then I did the rest from there. On a Friday evening. :roll:

Thats good even I can get that,but what use is it?

Pross

Just asked my 14 year old daughter with a predicted A or A* standard at GCSE and she didn't have a clue!!

rick_chasey

The kind of question presumably you find at the back end of a Level 2 SATS paper to see if you're level 5/6 or not, right?

3 minutes is quite a lot of time in an exam.

rick_chasey

Pross wrote:

Just asked my 14 year old daughter with a predicted A or A* standard at GCSE and she didn't have a clue!!

Predicting GCSEs results 2 years before they do them!

Christ.

garrynolan

johnfinch wrote:

I did

a + b = 80
b + c = 70

So, a + 2b + c = 150

This gives b as 50 then I did the rest from there. On a Friday evening. :roll:

Did it this way as well. Find it easier...