To ask if you do long multiplication/division regularly?

[BoyTree]

Please settle a debate for me!

Older son is doing long multiplication and it came up that it would have been more important to know the formal 'method' to complete the sum by hand/brain when calculators weren't so ubiquitous. He asked who would still be doing it by hand now and I was stumped!

I can't think of anyone who would routinely do long multiplication using the column method as part of their job, but felt sure I was probably overlooking some vital role. Does anyone here use it or know of a job where this skill would be vital?

I use it all the time, cooking large batches of food and calculating ingredients. I don't think I own a calculator and no desire to get ingredients on my phone

Long Division, yes, in my job. It's quicker to do it on paper than hunt for a calculator or fire up an app.

Let's try again

Yes I can do it. Can’t everyone?

[quote notimagain]There's still a lot around - including (with some differences) US measures. That's one of the more useful to laypeople type of maths.

Aviation related job..used to regularly have to look at figures in US gallons and convert to litres or better still kilograms..there were tables/apps etc available but the ability to at least grasp the conversions and get some feel for the credibility of what was going on was darned important..

Here's why..

en.wikipedia.org/wiki/Gimli_Glider[/quote]
I appreciate understanding the concept of conversion is useful. But year 6s are supposed to know how to convert from km to miles and back, without being given the conversion factor (they should memorise it). How many adults do you know who would (or even could) do that mentally/using a written method? I know 5miles=8km but if I want to convert I use an internet conversion calculator. Less accurately, I know the number of miles is roughly half the number of km.

Honestly, the most tedious y5/6 maths lesson I teach are the ones where they’re converting from inches to Cm, pounds to kg and so on. It’s tedious and they don’t retain anything useful from it (eg that a pound is about half a kilo and a km is about half a mile) because it’s loads of new measures and conversions, and some of the language they’ve never heard before. I just don’t think it’s necessary on the primary curriculum.

But year 6s are supposed to know how to convert from km to miles and back, without being given the conversion factor (they should memorise it

Did you know that in the GCSE, they get given the conversion factors?

filestore.aqa.org.uk/resources/mathematics/specifications/AQA-8300-SP-2015.PDF

But year 6s are supposed to know how to convert from km to miles and back, without being given the conversion factor (they should memorise it).

That's pretty silly. I'm 60 so the age when decimalisation and metrication came in. I don't remember having to learn exact conversion factors but there were useful rhymes - 'two and a quarter pounds of jam weighs about a kilogram', and 'a litre of water's a pint and three quarters'.

[quote chomalungma]But year 6s are supposed to know how to convert from km to miles and back, without being given the conversion factor (they should memorise it

Did you know that in the GCSE, they get given the conversion factors?

filestore.aqa.org.uk/resources/mathematics/specifications/AQA-8300-SP-2015.PDF[/quote]
EXACTLY. Which is why i think it’s ridiculous that 5 years before the GCSE they’re supposed to know miles to km!! As I say, this is part of the primary curriculum I’d ditch.

Have you seen many GCSE Foundation papers?

This is a non -calculator one from 2018.

To get a 4, you need about 50%.
A lot of this is the expectation at the end of Year 6

filestore.aqa.org.uk/sample-papers-and-mark-schemes/2018/november/AQA-83001F-QP-NOV18.PDF

And the division question near the start can be answered with 'the bus stop' or chunking.

They aren't bothered which - as long as you get the correct answer.

filestore.aqa.org.uk/sample-papers-and-mark-schemes/2018/november/AQA-83001F-W-MS-NOV18.PDF

You can even answer the multiplication question using any method - as long as you get the right answer.

Never. I do accounts for a living and haven't ever used it since school.

I think the example provided of knowing it should be roughly somewhere around 2,000 using your base knowledge rather than the exact number is a pretty good one. Almost anyone would use a calculator for that and even rain man would struggle to get the decimal points. I’d just be worried if someone thought it might 50 or 62,000 cos maths eh? What’s the point. That’s what calculators are for. But sorry for derailing the original long division question

I’d still expect a maths teacher to have the ability to calculate it with a pen and paper even if they would never would usually have to resort to and in real life use a calculator like anyone

As an aside I’m really good at doing arithmetic in my head and because some people are impressed by this human calculator type ability think I have some maths background. But never went beyond GCSE formally and no zero advanced maths. Just know how to add up, subtract, divide seemingly larger figures quickly in my head. Just a party trick thing and can’t count a pile of pins dropped on the ground visually like Dustin Hoffman in the rain man film which is probably bullshit

But being able to split something to rough figure before then using a calculator to get to the exact amount is good life skill and don’t expect most to be able to zone in to closer approximation than me. If I said £3,10 and they thought around £3 they would never be likely to get ripped off

Knowing miles to kilometres shouldn’t necessarily be maths question but think it’s a knowledge question and should know. Geography question? Can’t expect teachers to teach everything but would think someone was dim of rather whilst not knowing the exact conversion mile to kilometre rate they thought it was 8

How many adults do you know who would (or even could) do that mentally/using a written method? I know 5miles=8km but if I want to convert I use an internet conversion calculator. Less accurately, I know the number of miles is roughly half the number of km

I do. I also know that 1 mile = 1.609 km without googling. 5 miles = 8 km is close enough unless you're doing something like measuring elite sporting event distances though.

I can also convert celsius to fahrenheit and vice versa and once got a stunned wide eyed 'what an earth are you doing, that's witchcraft' comment from a junior colleague when I did it, going through the sums on paper, because we needed to know the answer and didn't have a mobile phone signal to google - we're professional scientists with physics degrees and all that, so it doesn't seem to be an unreasonable thing to do in my experience. I'm not even sure its an age thing as I have another young graduate in my team with a maths degree and he regularly makes me feel very incompetent numerically.

Yep, I use it daily in project management. I can also easily do the conversion between miles/km and Celsius/Fahrenheit but I rarely use the latter.

@BarbaraofSeville

How many adults do you know who would (or even could) do that mentally/using a written method? I know 5miles=8km but if I want to convert I use an internet conversion calculator. Less accurately, I know the number of miles is roughly half the number of km

I do. I also know that 1 mile = 1.609 km without googling. 5 miles = 8 km is close enough unless you're doing something like measuring elite sporting event distances though.

I can also convert celsius to fahrenheit and vice versa and once got a stunned wide eyed 'what an earth are you doing, that's witchcraft' comment from a junior colleague when I did it, going through the sums on paper, because we needed to know the answer and didn't have a mobile phone signal to google - we're professional scientists with physics degrees and all that, so it doesn't seem to be an unreasonable thing to do in my experience. I'm not even sure its an age thing as I have another young graduate in my team with a maths degree and he regularly makes me feel very incompetent numerically.

I’m not saying no one can or should be able to do it.I’m just saying I don’t think it’s the most essential knowledge for 10 year olds to have, and that I’d leave teaching it til secondary school.

I’m not saying no one can or should be able to do it.I’m just saying I don’t think it’s the most essential knowledge for 10 year olds to have, and that I’d leave teaching it til secondary school

It does seem strange that it's an expectation to know it in Year 6 but they get given the conversion in Year 11 and GCSEs.

A fun calculation is to change miles per hour into m / s.

I can't do long division. If I need to do something like that I use Google or a calculator.

Long division is primary school stuff.

Never use it. I hated maths and still do (I work with numbers lol), I just want the answer not sitting scrolling out a hundred ways to find the fucker!

My brother has a PhD in chemistry so he uses maths a lot!

My brother has a PhD in chemistry so he uses maths a lot!

So do I... lots of maths, far too much to do arithmetic by hand, or calculator come to that.