DS thinks he can teach himself to pass an exam in a week. AIBU to think he is wrong?

[user1494154933]

This is going to sound ridiculous and I wasn't going to post, as you'll probably call me stupid or irresponsible, etc.

My son is now 18. He isn't a 'genius' or anything like that. He did ok at GCSEs but didn't try hard at all. I used to try my best to get him to revise for him exams, he refused to and said it was pointless and exams don't help etc. which is ridiculous because as much as I do agree it's about memory, you clearly do need to know, anyway, he did ok and got accepted into sixth form, he decided not to go and got a part time job but did a part time photography course in the evening (he is still doing that).

I don't really know how it came about but I think I brought it up about how his exams were important and does he agree now he has matured and he was saying how he doesn't agree because exams aren't showing how intelligent you are, etc. and anyone can do them if they learn the exam technique. Last year (around december) he was telling me how he was going to prove it, he booked himself into the Maths AS exams for this summer (last year you can do these ones I believe). He hasn't learnt anything yet and I keep bringing it up (he spent £150 odd pounds for the exams (private candidate) and will sit them at his college he goes to part time) and he is telling me 'to wait and see'. He says when he has a week until the exam he will start learning the technique of it? I could slightly understand if a different subject, but he seems to think for Maths it works the best. I really don't understand his whole thinking behind this, but can't wait to be like WTF when he doesn't pass...

AIBU to think this is just stupid and not possible?

he was really happy about the area under curve question as it was a trapezium??

he said he can do those ones!

Apparently there's a bit of fuss that they were expected to solve
12x^2 - 59x + 72 = 0
Which doesn't surprise me as that's horrible.
My school doesn't do AQA though, so I won't be able to look at the actual paper, we do OCR.

Hope he does well op, keep us posted please .I would love to know how he does in August

noble I just did that equation. I think the 'trick' is recognising that to get the 59 you need an odd number somewhere, so having written out the obvious fact pairs it led me quickly to doing 3x9 and then also 4x8.
(Though that's easy for me to say not being in the stress of an exam)

OP when is the next paper?

factor pairs not fact pairs.

My cousin did this.
We all thought he would be knocked down a peg or two when he failed.
He didn't.
It turns out he's a super maths nerd and is now at Cambridge and he's going to walk out with a first.
Git

Teen many students wouldn't even know where to start with all the possible combinations. I don't know whether AQA routinely puts quadratics with that many possible combinations on, but I've never seen anything even close on OCR. I teach splitting the middle term, but then you have to list factor pairs of 864 which gets sillIy.
I think OP's DS would have gone straight for the quadratic formula which wasn't too bad, but many students forget they can use it without a calculator.

I was quite surprised to see them struggling with that quadratic, I think though that it's a case of being able to just see it once you've listed the factors though. Instinct goes a long way, but it's hard to teach that. I tend to always go for the middle pairs of factors to start with for each number.

Instinct goes a long way

See, I'm totally with the students on this, I'm rubbish at factorising quadratics where a>1. I look at some students muttering factors then writing down the answer with no working and quite frankly they might as well be doing magic. In my head is a hamster on a wheel and it has just fallen off. Then I look at other students and realise that they're totally on my side!

It has been quite an interesting thing to learn over the years, tbh. I've had students try to explain how their brain works it out and it just sounds gibberish to me. It has actually informed how I teach - don't assume that just because you can do something in your head that other people can too, only if you explain it well enough. I try to always provide algorithms for students who can't 'see' the answer.

I think it might be something to do with my working memory. I always need a pen and paper and to jot down every stage of working out, because I can't easily hold the numbers to the previous stage in my head and continue with the next step of working. With pen and paper, obviously I'm very good at maths!

For the quadratic could you not just use x equals negative b plus or minus the square root of b squared minus 4ac all over 2a?

I did that, but can someone tell me what they got please so I can see if I did it right? (Without a calculator!)

I pondered for a nano second using the formula but thought the numbers looked complicated so decided there must be an 'obvious' answer. So I wrote down 6,2 12,1 and 3,4 for the 12 and only 9,8, 6,12 for the 72.

Seeing I needed an odd number helped me rapidly to the answer. (Obviously 72 breaks down a number of ways but I was working on the theory that it was complicated enough without it being 18x4 or something like that.)

Goldfish, yes you could.

Spoiler alert:

(3x-8)(4x-9) so x =8/3 or 9/4

See it looks complicated but by the time you do the minus it only takes seconds to realise it is square root of 25 and the whole thing took less than a minute. But then I hated factor pairs and always avoided them! As soon as we learnt the formula in year nine I used it forever more!

I just double checked in photo math app and they did it the same way as me.

Oh do you HAVE to use factor pairs or do factor pair questions in the exam system? Or is it all solve for x?
(Not from the uk and ours was all solve for x)

In fact, I now realise I have no idea how to factorise equations anymore!

I read on twitter the other day that in other countries (might have been China?) they dont factorise quadratics. They always solve for x, get the roots, then if they need the brackets, work backwards.

My class would be able to factorise that because I teach trying all the factors. The other classes would find it difficult because they've been taught to split the x. None of them would remember they can use the formula without a calculator.

We do edexel, and our c1 exam looked relatively straightforward. The last question was a bit tricky but the rest were pretty standard.

that's really helpful insight Noble :)

One of the eastern european countries, forget which, will ask dd, doesn't do ratios at all. They do everything as fractions and use the colon as meaning something different.

The Dutch use the colon to mean divide. We've got a Dutch student teacher at school atm and she's always forgetting to put the line in the middle of our divide sign.

I teach trying all the factors.

That's a lot of factors though.

I teach trying all the factors, then I look around the class and say 'for those of you who can't get their head around it and will be stuck for ages trying all the combinations, here's another method'.

Obviously as a maths teacher I've spent quite a bit of time trying to get my head around factorising. Where a and c are prime I can manage, but as soon as the number of potential combinations creeps up, the hamster just falls off and refuses to get up.

Past papers will only get you so far and will never help to understand underlying concepts. If he gets a question that's taken out of context he is truly fucked. Had a level exam once, every question was new, the only way you could have passed it is if you actually understand. Which most people didn't and to no surprise most people came out crying.

I think doing the equation WITH a calculator actually complicates it. No individual part of the equation is more then basic maths.

Do they ask you to factories or is it just solve for x at that level?

That's interesting MrsAD. I wonder how they manage at international olympiads with all the different notation? I know that the the team leaders for each country mark them, but when there is an issue it goes to the overall judges.

It's Bulgaria that doesn't have ratios,

How does Bulgaria deal with problems like 'Albert, Bob and Caroline share £36 in the ratio 5:1:6'? Would they just say A, B and C share £36 so A gets 5/12, B gets 1/12 and C gets 1/2?

I think doing the equation WITH a calculator actually complicates it. No individual part of the equation is more then basic maths.

Calculators are used when the question says something like 'give your answer to 2 d.p. (At GCSE that's the hint that it doesn't factorise).

If the answer is a surd, I think it's easier to solve by completing the square than using the formula.

This thread has made me feel a bit panicked! I sat AS in both Economics and Government and Politics with a month of evening study as an adult and did well but maths is a different ball game.
I did really well with maths in my Leaving Certificate (Irish A level equivalent) and it nearly killed me getting through it.

I look forward to hearing his results.