48÷2(9+3) = ???

[ThePotsy]

http://www.purplemath.com/modules/orderops2.htm

This isn't "super advanced college math" here people. This is basic. Very basic. Link above even has a similar problem.

"This next example displays an issue that almost never arises but, when it does, there seems to be no end to the arguing."

16 ÷ 2[8 – 3(4 – 2)] + 1
    = 16 ÷ 2[8 – 3(2)] + 1
    = 16 ÷ 2[8 – 6] + 1
    = 16 ÷ 2[2] + 1
    = 16 ÷ 4 + 1
    = 4 + 1
    = 5

Notice they DISTRIBUTED the 2 to the 2 instead of using it to divide 16.

People who think it's 288 are the reason we can't have nice things. :p

[ck_taft325is]

http://www.purplemath.com/modules/orderops2.htm

This isn't "super advanced college math" here people. This is basic. Very basic. Link above even has a similar problem.

"This next example displays an issue that almost never arises but, when it does, there seems to be no end to the arguing."

16 ÷ 2[8 – 3(4 – 2)] + 1
    = 16 ÷ 2[8 – 3(2)] + 1
    = 16 ÷ 2[8 – 6] + 1
    = 16 ÷ 2[2] + 1
    = 16 ÷ 4 + 1
    = 4 + 1
    = 5

Notice they DISTRIBUTED the 2 to the 2 instead of using it to divide 16.

People who think it's 288 are the reason we can't have nice things. :p

I'm sorry, I missed everything you said. Mind repeating?

[reelizmpro]

No, you gotta look at the entire equation, not just a snip of it.

48 / 2(9+3)

= 48 / 2 x (9+3)

= 24 x (9+3)

= 24 x 9 + 24 x 3 (distributive applies here, no earlier)

= 288

IF it is 48/ [2(9+3)], then:

= 48 /[2x9 + 2x3] (distributive applies earlier)

= 48 / 24

= 2

What went wrong is you wrote 2x(9+3) while it's 2(9+3) or 2(12) = 24. Parentheses remain until you add (18+6) or distribute 2 into (12) to get 24. C'mon guys...basic algebra. 48 divide by...is a trap. MF parentheses >>>>> all. Keep doing the problem until you get rid of the parentheses first.

[tonywonder]

How, exactly, is it implied?

Isn't 2(9 + 3) the same as 2 * (9 + 3), the same way 2(4) is the same as 2 * 4?

Whatever, I'll just stick to what my calculator tells me...

the way you have to input it into the calculator is not the same as the way the problem is suppose to be solved based on the equation provided. had to use those calculators a lot in calculus and they constantly gave wrong answers without a little proper and more specific indication of telling the calculator how to apply implied multiplication.

it also really depends on how the original equation is written out on paper.



=2



=288

[frankenbeemer]

What went wrong is you wrote 2x(9+3) while it's 2(9+3) or 2(12) = 24. Parentheses remain until you add (18+6) or distribute 2 into (12) to get 24. C'mon guys...basic algebra. 48 divide by...is a trap. MF parentheses >>>>> all. Keep doing the problem until you get rid of the parentheses first.

This assertion is by no means as universal. Some texts apparently treat it this way, some don't. If you are asserting this is a universal rule you are on shaky ground.

[ck_taft325is]

Math e-peen all up in this bitch.

[reelizmpro]

the way you have to input it into the calculator is not the same as the way the problem is suppose to be solved based on the equation provided. had to use those calculators a lot in calculus and they constantly gave wrong answers without a little proper and more specific indication of telling the calculator how to apply implied multiplication.

it also really depends on how the original equation is written out on paper.



=2



=288

Right. However in 2(9+3) the 2 is a FACTOR of (9+3). It's a complete expression. It can be rewritten as (18+6) or 24. Unless it was (48/2)(9+3)....this is how to solve the problem and the answer is 2.
48/ [2(9+3)] = 48/24 = 2.

[tonywonder]

i completely agree

[reelizmpro]

This assertion is by no means as universal. Some texts apparently treat it this way, some don't. If you are asserting this is a universal rule you are on shaky ground.

The problem is sloppy math. Take it step by step. Write the problem on paper and show each and every step. Get rid of the parentheses in the proper manner. The parentheses remain until the expression 2(9+3) = 24.

48 / 2(9+3) Parentheses first
48 / 2(12) Parentheses first
48 / (24) Parentheses shown for thoroughness
2
Please understand the difference...
2(12) shows multiplication through distribution. Gets priority.
2*12 shows simple multiplication only.
note: there are no multiplication signs in this problem so don't add any.


OK I'm done. I just love math at this level. Much more fun than differential equations.

[Massimo]

I failed maths hard core and even I know it is 2. Not that really supports my statement. LOL

But this is how it should be done.

48/2(9+3)

=48/2(12)

=48/24

=2

The reason why 2(9+3) is not the same as 2x(9+3) because with 2x(9+3) the 2 is a separated from the bracket equation therefore you divided before multiply. But if it reads 2(9+3) then it is apart of the bracket equation and therefore comes before the division. This is simple mathematics.

[tonywonder]

What's the answer?

[Aptyp]

All day every day, as it is written, without any extra parenthesis, it's 288. You cannot assume 2 is factored out and you cannot assume (9+3) is in the denominator ... As it is written, you solve it.

48/2(12) would be the order you'd solve it in, and you solve left to right. Everything else is failing math. My ti-89 also showed 288. So did my ASME Casio. And even my phone...

[frankenbeemer]

If you believe that implied multiplication has a higher order than explicit multiplication the answer is 2. Unfortunately, this convention does not have the same consensus as PEDMAS. I don't know of any mathematician that doesn't follow PEDMAS, but there are many who do not believe that implicit multiplication (or multiplication by juxtaposition) takes precedence.

If you don't believe implicit multiplication takes precedence the answer is 288.

I prefer to follow the PEDMAS rules because they are globaly accepted. If I intended the answer to be 288, I would write the equation as it is written, just to be an ass to those who cling to a non-standard rule.

[frankenbeemer]

It's not sad at all... it's correct.



http://www.purplemath.com/modules/orderops2.htm

My apologies to Raxe for not noticing this earlier, that's what I was repeatedly asking for (even after you posted it), good point. I still assert that this rule does not have the global acceptance that PEDMAS does.

[tonywonder]

the reason it is implied is because you solve whats in the parenthesis and work your way out. therefore 2(9+3) is distributed for an answer then used to divide 48. and that IS using PEMDAS. in order for it to be the other way there needs to be clear indication that 48/2 is separate from (9+3) but its not. so 48/2(9+3) is showing that 48 is divided by the 2(9+3) and the answer is 2.