To be slightly horrified at how poor my basic skills are?

[primrosesandmaths]

In my professional, graduate profession, I have just been told I have to work out something as a percentage.

I have no idea how to do it.

I shall google - it isn’t an advice thread as such, but my maths is just dire and I can’t help wondering if this is common or whether I am an imposter in my role.

Actually that's not right because they are not really taught or shown how to do anything wisely.

My son's primary was awful with maths. It was nothing but number lines year after bleeding year. OK, I fully accept that number lines are a good way to teach the simplest of maths and to introduce the concepts of zero and negative numbers, i.e. stepping forwards and backwards. But when it comes to using number lines for multiplication and division, I started to despair. When they started using them for bigger numbers, i.e. into the hundreds not just for add/subtract, but also for multiplication and division, it was beyond a joke. Finally in year 6 (last primary school year), with a different teacher, they stopped using number lines and went onto crazily convoluted ways of calculations using some kind of blocking system which seemed to mean that even the simplest calculations took a long time. Never did they use the "bunk bed" approach which I always found very quick and simple and easy to learn. As I've said in a previous post, finally in year 11, the GCSE teacher spent a lesson on teaching the "old fashioned" method of long division - better late than never.

I realise I went into a generalised moan there. Apologies.

As I've said in a previous post, finally in year 11, the GCSE teacher spent a lesson on teaching the "old fashioned" method of long division - better late than never.

I have mixed views on those methods.

I think that the grid method for multiplication is good, because it's no more error prone, avoids some of the "magic" in the traditional long multiplication, and scales out to things other than integers. So you can multiply 27 x 33 and (x + 2) x (y + 7) using the same method. Multiplying polynomials together is pretty fundamental for a lot of post-16 maths and computing, and having a reliable way to do it is pretty handy. Is there a second-year computer science degree which doesn't at some point involve operations in finite fields defined by polynomials?

I think that "chunking" for long division is fantastic for integers, because it's basically standard long division with an acceptance that you might not be able to get the intermediate results off the top of your head. It mirrors how I do mental arithmetic.

But I think it's hopeless for the people it's being taught to, and agree with you they'd be better off learning "traditional" long division.

Consider 999 divided by 17. Traditional long multiplication breaks because you immediately hit 99/17, which you don't know. If you have all those mental shortcuts for multiplying by 2, 5 and 10 and if you can do addition and subtraction reliably, then chunking does roughly what I'd do in my head: well, 50 x 17 = 850, 5 x 17 = 85, 999-850-85=64, 64/17 is obviously 3 remainder something because 64/4 is 16, fiddle fiddle fiddle, answer is 67 remainder 13. The problem is that for the people it's aimed at, they're not able to do the quick multiplications by 5, nor the addition, so they would be better off accepting that they're going to need to do some trial and error and working out 99/17 by trial and improvement. And it doesn't work well for division of polynomials, either.

answer is 67 remainder 13

Answer is 58 remainder 13. Which shows how everyone makes mistakes typing :-)

kazzyhoward I think you misread my post. I didn't say "counting tins in a six pack" I said knowing the number of tins there were in 6 packs - being able to do in your head 6 x 6, 6 x 12, 6 x 24 based on your three examples of pack sizes.

Ok, I should have chosen a different number of packs. If I'd said "knowing the number of tins in 7 packs" I doubt whether you'd have converted that to "in a seven pack".

f sales are now £1375 and increased by 7% over the past year, what were sales level last year? An everyday example of the use of algebra.

You don't need algebra. If you understand percentages, you just divide the end figure by 1.07. Far simpler than algebra.

I disagree. That's a rule, which is easily forgotten. If you understand algebra and can derive the rule, you will have it available whenever you need it. (Last year) + 0.7(Last year) = 1375. To be able to comfortably to go to "divide by 1.07" you either need to understand that dividing both sides by 1.07 will get you there (algebraic manipulation) or you need a rule "divide this year by 1.07" ... and as people are saying all through this thread, if they're not using rules on a daily basis they forget them

OK, if you're being pedantic, not strictly a formula in exact terms, but a system/procedure for working out which numbers are prime. But I stand by my point - for school/average Joe Public purposes, simply remembering the first few prime numbers is far simpler and would take far less teaching time, and help reduce the "i can't do maths me" culture.

But what would be the point of learning 1,2,3,5,7,11,13,17,19 as a list if you didn't know what connected them all apart from having a fancy name? How would it help you know which were the next numbers in the list? And if you do know what they have in common, then you already have the means of working out whether 1379 is a prime.

The more you use mental arithmetic skills the better you get - I realised I’d stopped doing any mental maths and was always using excel at work or phone calculator eg for splitting a bill.

Now I’m making an effort to work out bill splits, change, distance/times on the treadmill (like if I’m running at 13kmph how many minutes per KM is that, or how long until I get to 5k).

I really liked maths at school, once we had a decent teacher. Got an A at A level but by the end of pure maths 3 I had reached the limit of my capacity to understand abstract concepts. (Fucking vectors)

so at least they understand fractions, percentages, So you are arguing for people to understand fractions and percentages, but when it comes to primes, you're not worried about understanding, you just want them to memorise a list?

Hey diddle diddle, the Median’s the middle;
You add and divide for the Mean.
The Mode is the one that appears the most,
And the Range is the difference between.

Now to read the rest of the thread :)

I disagree. That's a rule, which is easily forgotten. If you understand algebra and can derive the rule, you will have it available whenever you need it. (Last year) + 0.7(Last year) = 1375. To be able to comfortably to go to "divide by 1.07" you either need to understand that dividing both sides by 1.07 will get you there (algebraic manipulation) or you need a rule "divide this year by 1.07" ... and as people are saying all through this thread, if they're not using rules on a daily basis they forget them

Ignoring the typo there, it does seem odd to a numerate person that some people can't see that the two ways of looking at it are linked. I would absolutely just divide by 1.07, as I can quickly work out in my head that 1 + 0.07 = 1.07.

Op, out of interest, were you at school in the 80s/90s?

I am grateful that the maths teaching I got was so thorough (even though our teacher was horrific in her methods). Only a year or so ago I had to calculate the volume of water in our pond as a couple of fish were sick and I needed to work out how much medicine I should put in the pond.

I had to measure the irregularly shaped pond, the depth of it (quite variable), and then work out how much water there was in it.

I was glad of circle theory and trig, triangle stuff etc. Ihad little idea of how to start but I had all these tools tucked away in the back of my mind which gradually emerged.

20 years ago or so, I had to work out the optimum date for a meeting at work, where we wanted as many people as poss to come but they were all fairly high up and very busy; there were other conditions too but I can't really remember it all. Anyway, algebra popped into my head and I worked it out like that.

You never know how or why a bit of maths might come in handy, but it does.

Roundtable

Yes

Ignoring the typo there, it does seem odd to a numerate person that some people can't see that the two ways of looking at it are linked. I would absolutely just divide by 1.07, as I can quickly work out in my head that 1 + 0.07 = 1.07. I'm not sure whether you're agreeing or disagreeing - yes you'd do it in your head, but you're going through the logic that old amount times (1 + %inc) = new amount therefore to get the old amount you divide the new amount by (1+%inc). But if you've never done any algebraic manipulation you'd just have to learn it as a rule.

(And at last I've just seen the typo! Always interesting how many times you can read what you've written and only read what you meant to write and not what you actually wrote. 70% interest indeed.)

"Regular complaint in any education discussion on MN: "I / my children didn't when when we were 12 / 14 /16 / 18 that those jobs existed"." Exams don't only have to be taken at school. I left school (a shit school to be fair) with 4 GCSEs - since leaving school I've gained 4 more GCSEs, 3 A-levels, 2 vocational qualifications - one equivalent to GCSE level one to A-Level and 2 degrees. I've also learned 4 more languages to a level varying from "can get by on holiday" to "conversational" learning isn't limited to school.

"Just an old anecdotal here but I find my kids and grown up nephews and nieces are poorer at getting the required info from search engines than me and my siblings!" I've noticed this too. Despite "doing" 3 different IT based subjects at school my dd 17 struggles to search properly and had no idea how to use a spreadsheet or word processing software. She's learned since school via her admin based job but I do wonder wtf those subjects at school were supposedly teaching! Apparently it was "designing advertising campaigns" ie flipping simplistic posters - totally useless unless you're going to go into marketing/advertising/graphic design.

Yet in almost every job I've had since the mid 90's I've needed to know how to use word processing and since 1999/2000 spreadsheets and I suspect that's true for most people.

Thought so.

I am too. I have come to the conclusion that those decades were not our education system's best years. I'm sure there were schools doing it well but on the whole they weren't. Learning by osmosis; copying pages out of text books or learning by rote without understand the rules behind things were the norm.

I'm in a profession where I have had to learn how and why we do things in Maths and English etc. University was eye opening for me to say the least. They taught me to understand things I should have understood in primary/ secondary school.

I'm always a little aghast when people complain they can't do things because they weren't taught at school. If you're a functioning adult with google and a pen, you can learn how to do a simple percentage. Going through your life unable to work out a tip isn't accpetable.

Sideways how are you meant to know what you don't know?

I kinda get what you're saying but I've also come across people who THINK they know how to correctly calculate a percentage or spell a word and have been doing it wrong for decades with nobody pointing it out to them.

Got an A at A level but by the end of pure maths 3 I had reached the limit of my capacity to understand abstract concepts. (Fucking vectors)

My sympathy. Oddly I did better on the paper after that, which was mostly imaginary numbers. I think I knew I wasn't going to understand them in any meaningful way so just learned to turn the handle; whereas vectors felt like something that ought to make sense but was always just out of reach.

I was also garbage at Mechanics having dumped Physics. DH used a lot of vectors in his Engineering degree so I'm sure it's the same brainwork and not within my power.

if you're a functioning adult

Questionable

Aaargh bloody vectors! Yes, MrsH, they should make sense but.... just aaargh!

I only care about these vectors.

And not even that much.

A letter to the Guardian by Kenneth Ducker which is vaguely relevant to this discussion: "I well remember some 60 years ago on the morning of our 11-plus maths exam our teacher looking at the paper and saying “Shit, we haven’t done decimals”. This was followed by a 20-minute delay as we did a crash study of them. It worked – and increased my vocabulary"