Maths Test! 2(1+2)2/(1+2)
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NickyJ
Retired Narrator
But that simply isn't how it works. The a+b is multiplied by 2 because it is impossible to do anything else. a+b is as reduced as it can get, so you just move on to multiplication. However, 1+2 is added first because they can be mathematically added. Therefore, add 1+2, then multiply.
If you want to invent a new form of mathematics, be my guest, but at the moment, there is only one proper way that will give you exact results.
Terxpahseyton
Nobody
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Wait, are you seriously contesting that 2(a+b)=2a+2b?
Best anecdotal evidence against the US-education system ever.
Best anecdotal evidence against the US-education system ever.
Kennigit
proud 2 boxer
he got it wrong though because it's 0.5(1+2). 6 * 0.5(1+2) is what he meant to write, if pre-trolling.
anyways also thanks to other posters for having the congruent and all talk. Made this thread almost half decent.
NickyJ
Retired Narrator
Who is contesting that?
Actually, discussion of this issue almost always tends to look like evidence the other way, though there are likely confounding factors. The proportion of Americans who incorrectly repeatedly assert that the worse interpretation is better (in this case that's answering 9) is at least no higher than that proportion in other countries. Anecdotally, it seems to be significantly lower compared to some certain nationalities.
muhtesem insan
Amateur Revolutionary
it is 9 of course but i wanna explain why some one of them found it 1. In some calculators implicit multiplication has priority over explicit for ease of use.
I'm going to need some help here. I've been away from mathematics for a couple of years but I'm intending to go back to it in September. I keep getting
6/2(1+2) = 1
Order of operations (with irrelevant operations removed): Brackets -> Multiplication -> Division
So the expression should be the same as
6/(2(1+2))
Since 2 is involved in multiplication and division, you should do the multiplication before the division
= 6/(2(3)) = 6/6 = 1
But what I'm seeing a lot of here is
(6/2)(1+2)
where the division takes precedence over the multiplication.
= (3)(3) = 9
The expression
2(a+b)=2a+2b
means that if you choose to calculate 2(a+b) by adding a+b first ad then multiplied by two, you will get the same answer as if you multiplied by 2 first and then added 2a and 2b. There is a mistake in Cardgame's calculation but it's not on the line you picked out.
The more general expression
x(y + z) = (xy + xz)
means that it's acceptable to add first or to multiply first. The two approaches give the same answer.
What Cardgame should have done is
6/2(1+2) = 6/(2+4) = 6/6 = 1
The (deliberate?) error is getting rid of the brackets after initial multiplication and before the addition that they initially contained.
6/2(1+2) = 1
Order of operations (with irrelevant operations removed): Brackets -> Multiplication -> Division
So the expression should be the same as
6/(2(1+2))
Since 2 is involved in multiplication and division, you should do the multiplication before the division
= 6/(2(3)) = 6/6 = 1
But what I'm seeing a lot of here is
(6/2)(1+2)
where the division takes precedence over the multiplication.
= (3)(3) = 9
The expression
2(a+b)=2a+2b
means that if you choose to calculate 2(a+b) by adding a+b first ad then multiplied by two, you will get the same answer as if you multiplied by 2 first and then added 2a and 2b. There is a mistake in Cardgame's calculation but it's not on the line you picked out.
The more general expression
x(y + z) = (xy + xz)
means that it's acceptable to add first or to multiply first. The two approaches give the same answer.
What Cardgame should have done is
6/2(1+2) = 6/(2+4) = 6/6 = 1
The (deliberate?) error is getting rid of the brackets after initial multiplication and before the addition that they initially contained.
muhtesem insan
Amateur Revolutionary
in essence multiplication and division are same operations. so they have same priority.
5 years of maths at university and I never heard of that before. I pretty much always represented division by writing the divisor below the dividend, but I'm still having difficulty believing it never came up.
madviking
north american scum
In essence, there's no such thing as division; just inverse multiplication.
muhtesem insan
Amateur Revolutionary
probably they just assumed this was covered in elemantary school.
It's not like grades are based on lecture attendance. If that is such a basic aspect of mathematics (or at least of how equations are supposed to be read) it would have come up at some point in the course of exams or continuous assessment.
muhtesem insan
Amateur Revolutionary
it's Order of Operations it did never come up in maths classes in my 6 years of university education. (It did come up in programming classes though)
:suicide:Yes, in that case you first solve the divisor and the dividend and then divide as the last thing.
But when written on the single line (with "÷" symbol), you obviously follow order of operations from left to right, in which case division is done right after you solve parenthesis.
Math was one of my weakest subjects at school and I never learned it in Uni. But yes, that is elementary school stuff
