Maths homework -please help

[THK]

I have reached the answer through trial and error (it has taken me an hour with pennies), & yet I cant explain mathematically how to do this to my 8 year old. Im a rusty maths mum in need of help and hope someone can help give clear idea how to answer this!!

Q: queen esmerelda has 20 gold coins to share between 4 servants
Number 1 has 4 more than number 2
Number 2 has one less than number 3
Number four gets twice as many as number 2
How many do all 4 servants receive.
show workings out.

Thank you :)

I wish my DS had homework like this! I've just put it on a piece of paper to see if he can do it.

lostinafrica that was genius!

I was a bit lost when I read the op but

totally got the way you set it out...thanks!

He did it by trial and error: he started off by assuming each had 5. Then to get the difference between A and B, he took 2 from B and gave them to A, so A=7 and B=3, then he tested this against C and D and found it worked. He did it very quickly, but without a sniff of algebra.

He did "get" the algebraic method when I explained it to him, seemingly easily. Is there a website with similar problems, so I can find out if he did really understand?

I would have no idea how to do this. It makes my head hurt. I don't help with maths homework, because the demented methods mean I get the answers wrong.

here

Thanks!

MRZ - Thanks so much, but OMG this is all Dds homework since mid Sept lifted pratically 100% in some cases.
Can get a head start on the remaining worksheets now

Yay! Five minutes of fame.

Shame I wasn't around for it, really.

There is no way most 8 year olds could solve this using algebra.

Very bright ones could use problem solving techniques outlined in previous posts (this in itself is a highly developed skill)

Most others, would through their hands in the air alongside their mumsnet mums.

I would hesitate to give this problem, on it's own, to a Year 8 student

Sorry 'throw' not through

complexnumber it's from the National Strategies site aimed at 7 year olds

Really complexnumber? My Y3 class worked happily through a lot of these problems, and others like them, most of my middle ability+ managed well.
Bit worrying that you think a 13 year old in your class would struggle with it.

Its doesn't have an apostrophe when it's not a contraction BTW

THK - you're welcome although really lostinafrica did all the hard work!

I would be very suprised if any 7 year old solved this by using an algebraic approach. As opposed to a trial and error approach.

How would you expect a 7 year old to approach it?

I stand by my statement about 13 year olds struggling to solve this algebraicaly.

Given that I might be a little touchy over issues like this, I'd like to point out that over 50% of my students achieved grade A or higher last year at IGCSE.

Its doesn't have an apostrophe when it's not a contraction BTW

Given that I also hate seeing the wrong use of an apostrophe, I throw myself at your mercy for that one. Sorry, no excuses.

Complexnumber and Goblinchild

As per onimolap my dd arrived at her answer by taking bits away and adding elsewhere, she has had to think about the other worksheets but it hasnt been a hair pulling exercise.
However I would like to ask you both as I assume you are teachers is using trial and error wrong and should she be using a formula way to answer these types of questions or is it not so important at her level?
Which is what I suppose I was getting at originally in the fact I couldnt explain how to do it logically!
Appreciate your input.

She's 8, not a problem at all.

Either way she's thought about it and come to an answer. I've tutored many 15/16yr olds who wouldn't be able to answer it either way.

LostinAfrica
Im so thankful for your straightfoward explaination yesterday - Ill definately be tracking you down in future :)
The email back from the teacher this morning says she expected the children would work out as follows:
X+4+X+X+1+2X=20
5X+5=20
20-5 as the 5 has to move over to the number side
5X=15
X=3

Think Ill stay with the bags thanks

At 8 , I remember starting to learn that stuff in year 8 (13yrs). I would have thought there'd be a danger of them forgotting stuff as they aged.

Climberchick -thanks for reassurance. I know my maths is pretty basic & I dont want my child to inherit my fear of maths as she seems to enjoy it and is doing well.

Climber Chick - me too.. and I went to a good school ( believe it or not)!
But then my maths is weak so maybe other kids were being taught it earlier than I was by which time it made no sense whatsoever.

apols for the typos I'm a bit tipsy

fwiw i was in top set and 'x' is just a maths way of saying bag

(it's only 9pm here)

I'm a bit surprised the teacher's expected formal algebra, THK - although as ClimberChick points out, bags and 'x's are the same thing, really. But I find that a lot of people go into instant panic mode when they see 'x's whereas with bags they follow the reasoning and realise they do understand it! :)

Missed this

I love algebra - one of the most useful mathematical skills IMO.

I forgot to say, that I think one of the most useful parts of learning for this excercise is the 'changing of expression'.

To confidently know that 'bag 2 has 1 less than bag 3', is the same as saying 'bag 3 is the same as bag 2 + 1' means that you can change everything into terms of bag 2.

It gives a really good foundation skill for simultaneous equations in secondary school.

(Or person 2/person 3, since my bags were all the same size. )