48÷2 (9+3) argument

[SinghDude]

Bodmas v Bomdas ...

..As taught in primary school the answer will always be 2.


No need to over elaborate ...

 

[Dylan_G]

On a Casio fx 991EX PLUS : 48÷2(9+3) = 2 but 48÷2x(9+3) = 288. Its all about notation.

 

[Swa]

:facepalm:
Not this thing again.

 

[Celine]

with my CASIO ƒx-82ES PLUS i get 2, Google vs Casio; ill go with my CASIO

i'm taking it you did math's literacy at school instead of mathematics.

 

[GreyBush]

The notation sucks, let it go guys. You're arguing over an equation that's poorly defined.

Exactly, in the real world no one ever uses the ÷ sign, it's almost always expressed as a fraction.

 

[noxibox]

Wrong, 2(9+3) is not 2x(9+3), its (2*9+2*3)

Yes, that's what the distributive property says. Simply that adding the numbers first then multiplying is the same as multiplying each individually, then adding. It doesn't change precedence because 2(9+3) is just shorthand for 2*(9+3). It doesn't somehow make the 2 part of the brackets.

You're arguing over an equation that's poorly defined.

Not it isn't. There is absolutely no ambiguity in that equation.

 

[Mike Hoxbig]

Not it isn't. There is absolutely no ambiguity in that equation.

It is, because it's dependent on the interpretation. There is no way to tell if the person defining it meant for (9+3) to be part of the numerator or denominator.

 

[Archer]

It is, because it's dependent on the interpretation. There is no way to tell if the person defining it meant for (9+3) to be part of the numerator or denominator.

I say there is no ambiguity, because if you wanted it to be part of the denominator you would have used brackets to indicate it. Why bother thinking about hidden and implied things, this is maths!! Not a chat with your wife

I think people are used to seeing equations similar to 5+2(x+y), and so it has become a habit to associate the number with the brackets.

 

[biena]

This is a feature of the calculator, financial one usually uses the left to right method, scientific calculators are setup to use algebraic method, some clever calculators can even switch between the 2 modes.

As for order of operations, keep in mind that there are two different methods:
- chain (essentially left to right)

- algebraic

The chain mode of operation means that the calculator will perform calculations as they are entered (i.e., a literal "left to right" mode).

The algebraic mode of operation uses the following hierarchy:

1. Parentheses
2. Exponents
3. Multiplication and Division
4. Addition and Subtraction

 

[noxibox]

How about this - 4(3-1)^2? If we follow the idea of the distributive property uber alles the result is 64. Which is wrong, the answer is 16.

It is, because it's dependent on the interpretation. There is no way to tell if the person defining it meant for (9+3) to be part of the numerator or denominator.

As written there is no ambiguity, not mathematically.

 

[Mike Hoxbig]

I say there is no ambiguity, because if you wanted it to be part of the denominator you would have used brackets to indicate it. Why bother thinking about hidden and implied things, this is maths!! Not a chat with your wife

I expect the concept of parentheses to be lost on people who still use ÷

 

[Quantum Theory]

Yes, that's what the distributive property says. Simply that adding the numbers first then multiplying is the same as multiplying each individually, then adding. It doesn't change precedence because 2(9+3) is just shorthand for 2*(9+3). It doesn't somehow make the 2 part of the brackets.

Sorry, but that is not true 48 ÷ 2 x (9 + 3) = 288 and 48 ÷ 2(9 + 3) = 2...

I realise this is not what you were taught, so you think we're wrong, but we're right.

 

[The_Ogre]

No matter how I look at this I still get 2, so I'm bowing out

 

[GreyBush]

I expect the concept of parentheses to be lost on people who still use ÷

or say "divide" instead of "over".

 

[nakedpeanut]

Sorry, but that is not true 48 ÷ 2 x (9 + 3) = 288 and 48 ÷ 2(9 + 3) = 2...

I realise this is not what you were taught, so you think we're wrong, but we're right.

^^ this..
Because
48 ÷ 2 x (9 + 3)
is the same as
48 ÷ 2 x 1(9 + 3)

 

[AyeFinch]

http://www.wolframalpha.com/input/?i=48÷2+(9+3)&dataset=

 

[noxibox]

Sorry, but that is not true 48 ÷ 2 x (9 + 3) = 288 and 48 ÷ 2(9 + 3) = 2...

I realise this is not what you were taught, so you think we're wrong, but we're right.

2 x (9 + 3) and 2(9 + 3) mean exactly the same thing. What operation do you think is happening with 2(9 + 3) (since it's not multiplication apparently)? And pray tell what does 2 x (9 + 3) equal, because it's not the same as 2(9 + 3) (apparently)? Perhaps 2 is a function?

And then what happens with 4(3-1)^2? Now you have a real problem (having thrown precedence out the window).

The distributive property has nothing to do with precedence. It states a property of multiplication and addition. It falls in the same category as associative and commutative.

 

[Archer]

Sorry, but that is not true 48 ÷ 2 x (9 + 3) = 288 and 48 ÷ 2(9 + 3) = 2...

I realise this is not what you were taught, so you think we're wrong, but we're right.

So then it should be easy for you to point us to the rule that proves you right...
/waits forever

 

[noxibox]

^^ this..
Because
48 ÷ 2 x (9 + 3)
is the same as
48 ÷ 2 x 1(9 + 3)

Which is the same as 48 ÷ 2 x 1 x 1(9 + 3) and 48 ÷ 2 x 1 x (9 + 3) and 48 ÷ 2 x 1 x 1 x (9 + 3). And indeed 48 ÷ 2(9 + 3).

 

[Quantum Theory]

*Yawn*