please could someone help me get and understand this maths question?

[ssd]

thanks, cant work it out at all

solve.

3a=3a-6 and a
... ....... ...
4 2 3


(the ... is meant to be a line, the "and" is a plus sign)

thanks

[schobe]

Agree with the responsibility thing but it's important to manage it.

ALWAYS or even usually having access to answers leads to over-reliance on it. Checking should be happening regardless of access to answers. If they're there, students mostly look at them after their first attempt. If correct, no need to check, which is not a great message.

Providing answers at a certain stage can be very useful though, as you describe Run.

[CumbernauldMathsTutor]

schobe Sat 08-Oct-11 10:53:18:

"Sounds like CubernauldMathsTutor favours the unrealistic, sanitised approach I mentioned earlier"

Schobe, I don't favour any particular approach. I just tutor according what is being taught in the student's school and what is in the student's textbook.

As it stands, I have not seen algebra questions with answers like 36/13 either in Standard Grade in Scotland or in GCSE in England.

Maryz, is your ds, 13, in Ireland in a private or special school?

[CumbernauldMathsTutor]

ssd, I assume that your dc is in S2. I would suggest that you simply use his school textbook. And you could borrow the revision guides available in libraries - they cover the Scottish curriculum. I am not at home at the moment, but I will check the revision guides I have and let you know the names.

For the purpose of clarification, it would be really good if you could get your dc's teacher to confirm if the question you posted had a mistake in it. I don't think I have come across 36/13 as an answer to a similar algebra question even at S4 level.

[ssd]

cumbernauld, I will get back with the right answer soon as I get it!

and thanks, I would get those books out of the library if I knew the name of them

[CumbernauldMathsTutor]

ssd,

www.leckieandleckie.co.uk

publish revision guides relevant to Scotland. I have found the following two for S1-S3:

www.leckieandleckie.co.uk/products/buy_online.asp?css=1&area=219&lvl=7&id=1985

www.leckieandleckie.co.uk/products/buy_online.asp?css=1&area=219&lvl=7&id=1986

The more readily available KS3 guides (England) would cover more or less the same topics. You can sometimes find them at The Works and Poundland at discounted prices.

However, I would suggest you follow your DS's own school text book.

As for the original question, I have looked at it again and think the last part might actually be a/4 (rather than a/3):

3a/4 = (3a - 6)/2 + a/4

The denominators are 4, 2 and 4. Their lowest common multiple (LCM) is 4. So to get rid of the denominators, multiply both sides by 4:

4 x 3a/4 = 4 x [(3a - 6)/2 + a/4]

3a = 2(3a - 6) + a

3a = 6a - 12 + a

3a = 7a - 12

Get all the 'a' terms on one side and the numbers on the other. Since there is a negative 12 on the right hand side, add 12 to both sides:

12 + 3a = 12 + 7a - 12

12 + 3a = 7a

Now subtract 3a from both sides to get the 'a' terms on one side:

12 = 4a

Dividing both sides by 4:

3 = a, written as:

a = 3

You can then check if the answer is correct:

(3 x 3)/4 = [(3x3) - 6]/2 + 3/4

9/4 = 3/2 + 3/4

9/4 = 6/4 + 3/4

9/4 = 9/4

As far as I know, a standard, age 13, algebra homework question similar to the one posted would NOT have 36/13 as an answer, either in England or in Scotland.

I haven't seen a similar question with a similar answer even in (age 15) Standard Grade Credit (Scotland) or GCSE (England)
exam papers.

[CumbernauldMathsTutor]

Maryz,

My comment: "But age 13 homework would not have such an answer!" was contradicted by:

Your comment: "Age 13 homework could easily end with 36/13 which equals 2 and 10/13. ds is doing loads of these atm."

Your subsequent comment: "ds is doing honours maths (two levels here) and would be middle of his class age wise. So not all Irish 13 year olds would be doing this level"

Your subsequent comment: "And the examples I gave you would have been the last questions from each of set of problems, so they would have begun easier."

So your "easily end with 36/13" was not quite true, and you were out of order to say: "You know, your tone isn't very nice, are you implying I'm lying?."

[CumbernauldMathsTutor]

Schobe,

"Sounds like CubernauldMathsTutor favours the unrealistic, sanitised approach I mentioned earlier where all answers are nice tidy round numbers."

I never said I favoured any approach so your comment is out of order.

Contrast this comment with your own earlier comment:

"I think tackling a much easier equation might be a better option at this point to firm up the basics."

Age 13 ARE learning the basics of algebra. Do you think an algebra question with 36/13 as answer is REALISTIC?

[ssd]

thanks for thsie links CumbernauldMathsTutor, Ill check them out

i still havent seen the homework answers from his teacher, I'll post back if i do

[GrimmaTheNome]

Age 13 ARE learning the basics of algebra. Do you think an algebra question with 36/13 as answer is REALISTIC?

Based on what my 12 year old is doing, why ever not?

[GrimmaTheNome]

I know they were very fond of 'neat' numbers pre-calculator - remembering applied maths A level with pi always approximated as 22/7 with nice numbers so you could work through an involved calculation without getting hung up on the arithmetic.

But 36/13 doesn't sound like an answer that should faze a 13 year old.

[schobe]

Cumbernauld, I'm sorry but you're a nutter.

[schobe]

You can have easier equations without necessarily having a nice integer answer.

Odd.

[schobe]

Out of order? This whole courtroom is out of order.

As you clearly think you're cross-examining us.

[schobe]

And:

YES IT IS REALISTIC, ESPECIALLY WITH A DECENT MATHS TEACHER.

Since we're shouting

[GrimmaTheNome]

There again I remember a lot of 'neat' angles as looking up trig functions in tables was a bind.

The thought occurs that Cumbernauld may have an expert yet distorted view of maths ability as presumably she tends to see the kids that actually need maths tutoring. I wouldn't have thought she'd be getting hired for any who've been perfectly comfortable with fractions like 36/13 since primary. And maybe we've distorted views because of the natural brilliance of our kids, this being Lake Woebegone MN

[schobe]

Don't get me started on doing fractions on calculators too. You can add, subtract, multiply, divide and cancel fractions on calculators so that nobody ever actually needs to understand how to do it.

Then when the last people who can do fractions die, the world will END.

[schobe]

Grimma - sometimes the ones being pushed into tutoring by mama and papa are perfectly good at maths, but not as much of a genius as would be desirable.



Also, was it just me that thought Cubernauld was male? Which is it CMT?

[GrimmaTheNome]

I was one of the first generation to use calculators (A levels '79) - my pure maths teacher would barely let us touch them, called them 'complicators'.

They didn't do fractions in those days though!