How do they teach maths at school these days?

[harrybarracuda]

I thought this was well known, but they're acting like this bloke deserves the Fields medal.

Maths trick blows people's minds on Twitter


The "fascinating little hack" involves flipping the numbers around to make things easier - and is described as "life changing".

https://news.sky.com/story/maths-tri...itter-11658556

[foobar]

So using this "fascinating little hack" what is 64% of 69 ?

[Jack meoff]

^Don't you know?

[foobar]

^ Please fill out the form before posting further...

[NamPikToot]

With Illegals?

[Troy]

Jesus H C
A first year junior school equation becomes a life saving hack...

What is the world coming to?

[buriramboy]

Jesus H C
A first year junior school equation becomes a life saving hack...

What is the world coming to?

I blame the EU.

[harrybarracuda]

So using this "fascinating little hack" what is 64% of 69 ?

Your IQ.

[Maanaam]

So using this "fascinating little hack" what is 64% of 69 ?

= 69% of 64. Did that in my head.

Obviously the "hack" is opportunistic for when you're trying to find a percentage of one of the easy ones: 1, 5, 10, 12.5, 15, 20, 25....etc.

[headhunter]

kids are learnt how to count from the age of 1 upwards,every day they count the no.of white sheets covering the dead bodies.

[lom]

So using this "fascinating little hack" what is 64% of 69 ?

Flip around, round up the multiplier to 70 which makes the multiplication much easier , multiply and then subtract 1% of 64.
This method will not only blow the minds of the Twitterers, it will make their heads explode..

[Topper]

what is 64% of 69 ?

Easy, that's the point I take my hands off her hips and start forcing her head down on myself.....

[foobar]

Obviously the "hack" is opportunistic for when you're trying to find a percentage of one of the easy ones: 1, 5, 10, 12.5, 15, 20, 25....etc.

Yes, its obvious now that I've pointed out the flaws and limitations

Flip around, round up the multiplier to 70 which makes the multiplication much easier , multiply and then subtract 1% of 64.
This method will not only blow the minds of the Twitterers, it will make their heads explode..

Ah yes, but now we are firmly outside the realms of the "fascinating little hack".

Of course we could just shift the decimal point one place and don't swap anything: 0.64 * 69

[harrybarracuda]

See Post #8.

We'll let you round up if it makes you feel better.

[lom]

Of course we could just shift the decimal point one place and don't swap anything: 0.64 * 69

I can't see that making any difference, it is still the same digits to multiply..
The 64's or the 69's multiplication table is not something John Doe is familiar with and the other multiplicand being a double digit doesn't make it any easier.
If you want to do that multiplication in your head then it helps to do either 0.64 * 60 + 0.64 * 9 or 0.64 * 70 - 0.64 * 1.

The square of the prime number 17 is simple to solve, everyone should know the 17's multiplication table and that the answer is 289.
Now do the cube of 17 in your head, easiest way to do 289 * 17 is to do it as 300 * 17 - 11 * 17..

[Looper]

Nobody needs to know this shit.

Everyone has a calculator on their phone.

In a generation the western world will all be like thai 7-11 check-out chicks.

Who needs grief like arithmetic.

Liberation from this kind of basic mental effort is what the information age is all about.

It is bringing us full circle on a glorious journey back to our natural hunter gatherer condition when the counting system that humans had to worry about consisted of 1,2,3, many

[lom]

Nobody needs to know this shit.

Everyone has a calculator on their phone.

No one needs to remember anything because google can instantly give you any information you need, eh?

In a generation the western world will all be like thai 7-11 check-out chicks.

You mean the ones who when your bill is 722 coins and you give them 1022 coins then they give you the 22 coins back saying that 1000 is enough.

Math is brain massage and stops the dumbing down process.

[fishlocker]

Your IQ.

Sorry, but that's funny.

[Maanaam]

Yes, its obvious now that I've pointed out the flaws and limitations

No, it was obvious before that.

Of course we could just shift the decimal point one place

...and get a wrong answer, wrong by a factor of ten.

[Simon43]

One of my online students is a little German-Chinese girl, about 7 years old. I'm teaching her Maths and French (God help her!). (I teach her using English and a bit of German and Chinese thrown in...)

Anyway, we're still at the very basic level of Maths, but it's fascinating to see her working out addition and multiplication in her head, without a calculator ('cos I told her not to use it - verboten!!). We've been covering mental Maths 'tricks', (such as multiplying 300 x 6,000 and just counting up the zeros etc and sticking them onto the result of 3 x 6).

Great learner. Her Maths skills are coming on well and she's learnt to say "fou le con" in French... (that's a joke!)

[harrybarracuda]

Sorry, but that's funny.

Who said it was?

[Maanaam]

without a calculator ('cos I told her not to use it - verboten!!).

Yeah, 7 is too young to be dependant on a calculator, but for my M1 students and up, although their Thai maths teachers forbid calculators, I insist they use them. They all know how to multiply and divide, so it's a waste of time getting them to work it out long-hand when the subject at hand is, say, the theory behind probablity or calculus.

Cue Lu and his sycophants.

[Simon43]

Maanaam, she's still picking up the basic numbers and she wants to do it in her head. Once we're onto complex stuff, then out comes the calculator.

Her Teutonic background (her father is German), is already well-instilled There's a page in her Maths book with shapes (circles, stars, squares etc), each with a line drawn through them to show 2 parts, mostly unequal in size except for one (the star shape).

'Which shape has 2 equal parts?" I asked her. "None of them" she replied. I gently indicated that the star shape was divided into 2 equal parts.

"No it isn't" was her reply. "Yes it is"/"No it isn't" etc etc

"OK, why isn't it?" I asked her. "Because there is a tiny black mark on the line" she said. Sure enough, when I used a microscope, I could just make out a tiny printing ink error that effectively meant that one of the halves of the star wasn't actually 'half'.

Bloody Germans

[foobar]

So using this "fascinating little hack" what is 64% of 69 ?

Of course we could just shift the decimal point one place and don't swap anything: 0.64 * 69

...and get a wrong answer, wrong by a factor of ten.

Well, I bow down to your superior knowledge, you being a v̶i̶s̶i̶t̶i̶n̶g̶ ̶p̶r̶o̶f̶e̶s̶s̶o̶r̶ professional in the field of advanced mathematics n'all.

But, can you show your working so dumb asses like me can learn and understand, how: 64% of 69 = 44.16 is the wrong answer by a factor of ten?

[harrybarracuda]

Well, I bow down to your superior knowledge, you being a v̶i̶s̶i̶t̶i̶n̶g̶ ̶p̶r̶o̶f̶e̶s̶s̶o̶r̶ professional in the field of advanced mathematics n'all.

But, can you show your working so dumb asses like me can learn and understand, how: 64% of 69 = 44.16 is the wrong answer by a factor of ten?

Derp.

Of course we could just shift the decimal point one place