SWMBO wanted a table protector for the new dining table we'd bought. It was an extending table and she'd found some suitable stuff at Dunelm Mills. So off we trotted. We needed 3.5m as it extended from 1300mm to 1800mm and they only sold the stuff by half metre lengths. It was £10/m.
I should've been suspicious when the shop assistant needed a calculator to work out what 3.5 X 10 was!
Got it home and there was only 3m. Took it back and explained, a manager appeared. They stated :"we all can't do mental arithmetic". I told them that to mitigate their losses, all I needed was an additional 1500mm length. I repeated this, but they didn't seem to understand. So I just said cut me a new 3.5m length.
|
Bulk of youngsters of today
Cannot Count
Cannot do their times tables
Cannot do fractions
Cannot do percentages
Why?
The Primary Teachers of today struggle with Primary Arithmetic as today's teachers were badly taught Arithmetic 10/ 20/30 years ago.
My, quite bright, 15 year old granddaughter was struggling with Algebraic Fractions a month back. An hour a week for 2 weeks sorted that and the last 2 weeks it has been Algebraic factors.
Test tomorrow so we will see how she gets on.
The older sister was equally poor but with 2 years effort and many hours many weeks, did 20 years of back papers. Scored 91 in Higher Maths 2 years ago (Higher Maths = AS Level in E&W).
20 years of old papers saw her cover most of the awkward questions likely to turn up. She did the whole paper, I covered the ones she struggled with week by week.
On Saturday looking at buying a £3,000 bit of furniture, the owner offered 12.5% off and said that will be £2,775 to which I said £2,625.
The assistant, in disbelief, then chirped in "How do you know that?"
Fractions I learned in Primary. 12.5% = 1/8th
|
|
Get charged say £5.35 and give the assistant £10.35 and you can see the brain go into meltdown.
|
|
I was asked by a barmaid what the time was (insert your own joke here). I pointed at the clock behind her and said the time. Thanks, she said, I can’t read a clock with hands.
|
In my head I was thinking 12.5% is £125/£1000. Three of those is £375.
Even if I use a calculator for odder amounts I always round the numbers a bit and do something like that as a gross error check.
I spent 20 years writing and using spreadsheets. If it was important I would always do a sense check or build in a reconciliation. I still made mistakes but it was usually I who found them!
www.joe.co.uk/politics/george-osbornes-austerity-measures-were-based-on-a-spreadsheet-error-360105
|
My youngest son was sitting the prelims in his final year at school.
It was a question on a field gun and the speed of recoil when a shell was fire.
In the last line after much calculation he had the field gun coming back at roughly 30mph instead of 0.03 MPH - he had multiplied instead of dividing in the last line.
Always check your answer - is it reasonable? It would have killed more behind the gun than in front!
1st in Process Engineering 4 years later, and now a senior engineer on large North Sea projects
|
Slide rule.
You had to do a rough mental calculation to guess the magnitude (and where to put the decimal point).
I offered my last one on Freegle. The guy that collected it was going to demonstrate its' use to his grandsons. I bet they were delighted!
|
>> Slide rule.
>>
AKA "Guessing Stick".
|
All this mental arithmetic stuff... I am of the calculator generation and love spreadsheets- but FB's furniture maths wasn't a problem for me. I just wish I was better at algebra, I passed "o" level maths but have forgotten pretty much all of it.
My kids on the other hand - well, the only reason Miss Z stopped after an A at AS level was because she wanted to concentrate on chemistry, biology and physics - and the maths homework just took a bit longer to do. Master Z, after a break due to covid / surgery / illness, is back doing his Maths degree and is planning a masters in some weird mix of maths and biology.
I was visiting a warehouse recently and stock pickers were doing mental maths on units.
Its also why we see stuff sold in 12s. There are far more factors than for 10s.
|
Bit of mental maths trivia. I was told that the betting odds of 13/8 and other “8” odds hark back to half crowns being 8 to a £. It sounds plausible.
And the florin, at 10 to the £, was an early foray into decimalisation.
Last edited by: martin aston on Tue 1 Oct 24 at 08:32
|
There is a short sci-fi story from the time when computers were as big as factories and this thread reminded me of it.
A spaceship is travelling the solar system when an unexpected meteor shower damages the ships computer and communications.
The crew are stranded, unable to make the calculations to get home. One of the scientists is Chinese and remembers abacus from his youth and they rig one up for each crew member and he teaches them how to use them quickly for complex maths.
In teams they do the calculations and get home safely.
Always good to know the basics!
|
|
I must admit I've got lazy recently and ask either Alexa or Siri to add / multiply etc some numbers together instead of working it out myself or launching my calculator app.
|
Young folk may have trouble with basic sums.
But they can install an app and have it working on a smartphone, while many over 60 are trying to remember their play-store password - assuming they know there is an app to solve their problem.
Which group is better prepared for survival in the mid 21st century is debatable.
|
|
That’s true. How often do you actually need to perform mental arithmetic in your daily life? A useful skill but you lan live without it.
|
My primary teacher in what we now call year 4, Mrs Shepherd, was a stickler for tables. Half an hour a day prowling round the class pointing at students and asking stuff like 7*9. Woe betide if you got it wrong and if it wasn't on the tip of your tongue 'too slow'.
Working today. My caller was 16 and in school 3 days a week for 7 hours.
Found myself using my calculator for the 3 times table.....
|
|
Years ago, my job entailed converting denary to hex and vice-versa. A colleague and I would check each others work for errors. He had a scientific calculator, I didn't. We'd race each other for the answers, me on pencil and paper. It would be nip and tuck, but I didn't have to open a drawer and switch it on.
|
I think I might have told the Scientific Calculator Story before.
A younger brother went to University in 1971. Engineering and needed a calculator.
My parents bought one for him nearly £400 (about £5,000 today's money)
Within 12 mths it was stolen at university and they claimed on the house insurance. Receipt had been kept and the £400 was paid out. He then went to buy the "new model" it was £300!
Today a cheap Scientific Calculator is under £5, a top of the range Casio £30+
The £400 investment paid off 1st Class degree. Now a "wealthy pensioner" - he was the biggest shareholder in an engineering consultancy with some 70-100 employees depending on demand over the 40+ years he worked.
|
My best friend at school had a year out of University after exam issues.
On a visit back home we went out for a pint, and he said he'd had some good news - he'd won £10K on "Spot the Ball" in the local paper. (A very large amount of money, as it was a multiple roll-over week). I didn't believe him at first.
Being a Civil Engineering student, one of the first things he bought was one of the very early Sinclair calculators. It would have been 72/73.
My memory is that it was somewhere in the region of £100, which was a phenomenal amount of money for a student in those days.
|
The Sinclair calculator....A bit of history...
Texas Instruments - the chip maker had designed a "calculator on a chip" for manufacturers to use in making calculators.
Sinclair and a colleague went to the States and built one.
The squeezed the code in and ignored error checking - there was no room and realised that you could pulse the LED display to save power - due to humans' persistence of vision. It meant that their calculator could be tiny compared to the much larger models that the competition had.
|
|
I recall being handed out early LED calculators on a training course (early 70s?). Before the end of the day we were all asking for new batteries.
|
I worked during student holidays in a large British railways accounting office. it would have been at the very end of the 60's.
It had one electronic calculator, which was of desktop size, and had to be signed in and out (only allowed for the most onerous/valuable calculations).
I'm certain it was a Casio, and would have had (I think) a panaplex or VFD display.
|
|
Well a slide rule was used on Apollo 13, according to the NAS museum.
|
Slide rules were certainly a thing for Maths beyond O level in 1977/8 and possibly for those aspiring to top grades at O level too.
Today there are still circular devices which AIUI provide some slide rule type functions for private pilots.
|
Ready Reckoners were what we used to try to sneak into maths exams when I was a scholar.
I can remember sometime in the seventies when someone brought a pocket calculator into work and the whole shift were standing round in amazement as it gave instant answers to the various sums people came up with.
|
Let me tell you a story - Falkirk Bairn
