What is 1+2x3?

What is 1+2x3?

53 posts
20 July 2013
StreetModel
Photographer
StreetModel
On my basic calculator, the answer is 9. On my Nokia phone in Portrait it is also 9, but on my Nokia turned Landscape, it is 7. On my Samsung phone either way, it is also 7.

So which is right?
Posted 20 July 2013
Andy_B
Photographer
Andy_B
It's 7

You need to know maths to use a calculator... and multiplication has higher precedence in the expression than addition.

Posted 20 July 2013
Buddygb
Photographer
Buddygb
It's 7.

http://en.wikipedia.org/wiki/Order_of_operations

B.

Posted 20 July 2013
NATKINS
Photographer
NATKINS
With proper notation the possibilities should be:

1+(2x3) = 7

(1+2)x3 = 9

QED 1+2x3 = 7 or 9 !!!

Nick

Posted 20 July 2013
seanb
Photographer
seanb
BODMAS to remember the order:

B - Brackets first
O - Order (exponent - i.e. squares, square roots)
D - Division
M - Multiplication
A - Addition
S - Subtraction

Technically it's BO(DM)(AS) as multiplication and division have the same precedence, as do addition and subtraction, but it's less catchy that way.

So the answer, as it's written, is 7.
Posted 20 July 2013
Andy_B
Photographer
Andy_B
NATKINS

With proper notation the possibilities should be: 1+(2x3) = 7 (1+2)x3 = 9 QED 1+2x3 = 7 or 9 !!! Nick


no
Posted 20 July 2013
SMILESPHOTO
Photographer
SMILESPHOTO
To get the answer 9, it would need to be written (1+2)x3 or, technically, 3(1+2). As others have said, multiplication takes precedence over addition so the sum should be read as 1+(2x3). That's your maths lesson over with for today Dave - as it's the weekend we won't set you homework!
Posted 20 July 2013
1884photo
Photographer
1884photo
Just forget about it! Get out in the sun! Or cloud! Depends what day you read this.

Posted 20 July 2013
StreetModel
Photographer
StreetModel
I am aware of BODMAS, but it worries me that some people doing important calculations are using basic calculators and others are using newer ones...

It reminds me of a rocket science problem which was attributed to a 'failed' probe deployment because one side (USA) were working in imperial and the other side (French, I think) were working in Metric - the net result was the probe was 'shot' from its position towards the planet rather than 'lightly floated'

Posted 20 July 2013
Andy_B
Photographer
Andy_B
StreetModel

I am aware of BODMAS, but it worries me that some people doing important calculations are using basic calculators and others are using newer ones...


It's not about what the age of the calculator is. It's about knowing maths. If you don't know maths you will get it wrong. 

Most calculators tally a single operation at once. That will always give the wrong answer if the person using it types the '+' first.

Maybe we shouldn't let idiots do important calculations.
Posted 20 July 2013
NATKINS
Photographer
NATKINS
Andy_B

no



Any explanation as to why I fell short of your approval?

Always willing to admit I'm an idiot...

Nick
Posted 20 July 2013
Edited by NATKINS 20 July 2013
Andy_B
Photographer
Andy_B
NATKINS

Any explanation as to why I fell short of your approval?

Always willing to admit I'm an idiot...

Nick


While (1+2)x3 is always 9
and
1+(2x3) is always 7

1+2x3 is always 7 and never 9.
Posted 20 July 2013
mantisphoto
Photographer
mantisphoto

Using a script calculator app on my android tablet... this is the answer!!!!! :P
Posted 20 July 2013
Photoimager
Photographer
Photoimager
I thought these tiresome things only appeared on US based sites.

Yes BIDMAS ( to be National Curriculum correct, it used to be BODMAS, USA uses PEDMAS etc ) is one decider.

However, as well as 7 the answer can also be 11, 12 and 13. By the same token 1 + 1 can equal 10.

Now for the real confusion about some mathematics I learned whilst at Primary school but has never been in GCSE but was in the older O-level.


Posted 21 July 2013
seanb
Photographer
seanb
Photoimager

By the same token 1 + 1 can equal 10.


There are 10 types of people. Those who understand binary and those who don't.


Posted 21 July 2013
To reply to this thread you must be a member. Click here to join