i just learnt some new maths(!)

[JulieandTony]

Sometimes it's quicker to recognise a pattern than it is to do a calculation longhand. I don't remember most of my tables these days, for example if I want 7 * 9 I can calculate 7*9=7*10-7 = 63



Before electronic tills made things easy if you gave a shopkeeper a tenner and he was short of change he would ask for the £2-4s-0d and give you a fiver change. Sometimes I think they did it deliberately to confuse the customer and short change them.

My father was a bank clerk and his father a maths teacher. Dad could add up a column of numbers (£-s-d) quicker than the younger members of staff could use an adding machine.

My dad was totally useless at maths (and they had a shop!) so couldn't help me one bit at school or my mum with the shop accounts; but once in front of a dartboard he could add up and work out "the out" from any number, in the minimum or safer number of darts.


I think it was a 25 for out - I said 5 and double 10 - he said no, do 9 double 8 - 'cos if you miss the double 8 and get 8 you're on double 4 then double 2 then double 1

Played a lot of darts my dad

 

[Cyberprog]

I'm slowly teaching my missus that the endcap "deals" in supermarkets are not always the best deal for you!

Mind you, my maths skills topped out at GCSE, I dropped maths at A level as it was doing my brain in. Pointless subject unless you're doing something really high level IMHO, computers can do all the maths for you these days.

Never needed algebra in my working life!

 

[JulieandTony]

I'm slowly teaching my missus that the endcap "deals" in supermarkets are not always the best deal for you!

Mind you, my maths skills topped out at GCSE, I dropped maths at A level as it was doing my brain in. Pointless subject unless you're doing something really high level IMHO, computers can do all the maths for you these days.

Never needed algebra in my working life!

The thing is in supermarkets they display a unit price as well eg

So toilet roll (andrex puppies 12 roll) £5.00 (41.7p/each)

- so you don't need that much maths these days

 

[rtbcomp]

My dad was totally useless at maths (and they had a shop!) so couldn't help me one bit at school or my mum with the shop accounts; but once in front of a dartboard he could add up and work out "the out" from any number, in the minimum or safer number of darts.


I think it was a 25 for out - I said 5 and double 10 - he said no, do 9 double 8 - 'cos if you miss the double 8 and get 8 you're on double 4 then double 2 then double 1

Played a lot of darts my dad

That and working out how many points someone needs to win F1 depending on what points everyone else has got, or what balls to pot in a snooker match.

 

[The_Yellow_Ardvark]

 

[Maker]

View attachment 171692

By the same logic;

1 + 2 = 3
"sImPliFy bOtH sIdEs wIth ( + 2)"
1 = 3

 

[bigegg]

Never needed algebra in my working life!

i bet you have.
without realising it.

algebra is NOT maths.
its just a shorthand way of writing a question.

for example:

what is half of 80?
can be written as

2x=80
x=80/2
x=40

you will use algebra, you just dont realise it...

 

[bigegg]

View attachment 171692

(2x2)-(2x2) doesnt lead algerbraically to (2-2) x (2+2), hence the disparity.

4 - 4----------> 0 x 4 ¿??????¿

 

[rtbcomp]

View attachment 171692

That resolves to 0 = 0

 

[The_Yellow_Ardvark]

It can be proved by two methods:

Method 1

20 - 20 = 25 - 25

(5*4) - (5*4) = (5*5) - (5*5)

Taking 4 common from L. H. S and 5 common from R. H. S

4 (5-5) = 5 (5-5)

Cancelling (5-5) on both sides

So we get, 4 = 5

4 can be written as 2+2

Therefore, 2+2 = 5

Method 2

-20 = - 20

16 - 36 = 25 - 45

4² - 4*9 = 5² - 5*9

Now adding 81/4 on both sides

4² - 4*9 + 81/4 = 5² - 5*9 + 81/4

4² - (2 * 4 * 9/2) + (9/2)² = 5² - ( 2 * 5 * 9/2) +(9/2)²

Using property : (a-b) ² = a² - 2ab + b²

( 4 - 9/2 )² = ( 5 - 9/2)²

Square rooting both sides gives us

( 4 - 9/2 ) = ( 5 - 9/2 )

And now cancelling - 9/2 on both sides

We get, 4 = 5

Again 4 can be written as 2+2

So, 2+2 = 5

Hope you like it!

 

[bigegg]

division by zero: you just proved infinity=infinity.

 

[rtbcomp]

It can be proved by two methods:

Method 1

20 - 20 = 25 - 25

(5*4) - (5*4) = (5*5) - (5*5)

Taking 4 common from L. H. S and 5 common from R. H. S

4 (5-5) = 5 (5-5)

Cancelling (5-5) on both sides

So we get, 4 = 5

4 can be written as 2+2

Therefore, 2+2 = 5


Hope you like it!

You don't cancel a term by deleting it, you divide each side by the result of the term, ie 0. so you get :-

division by zero: you just proved infinity=infinity.

 

[Kayos]

division by zero: you just proved infinity=infinity.

Yes but some infinity is bigger than others

 

[bigegg]

Yes but some infinity is bigger than others

thats philosophy, not maths.

plus these are the same infinity:
(real number)/zero

 

[Burdekin]

I've recently bought a copy of "Calculus for Dummies" and just realised I can't read.

It’s one thing being clever enough to learn and understand calculus, can you believe how smart Newton must have been to invent it.

 

[Kayos]

thats philosophy, not maths.

plus these are the same infinity:
(real number)/zero

No it's not philosophy

I may not be totally correct but how many numbers between 0 and 1? Is one infinity and the infinite hotel example is another, smaller infinity

 

[Pete.]

It’s one thing being clever enough to learn and understand calculus, can you believe how smart Newton must have been to invent it.

He wasn't that smart or he'd have sat under a cherry tree

 

[RichardM]

I'd just like to say I only need to cut a pizza in half, one half for MrsM, one for me, my half is usually a little bigger

 

[Screwdriver]

It’s one thing being clever enough to learn and understand calculus, can you believe how smart Newton must have been to invent it.

...and the cat flap.

 

[roofman]

How did i know this thread would turn into an intelligence award ceremony where all awards are self delivered