48÷2(9+3) = ?

[grundle]

Texas Instruments TI-85 says:

48÷2(9+3) = 2

But Texas Instruments TI-86 says:

48÷2(9+3) = 288

[Bikkuri]

I am 40 years old... 4 years USAF and 3 years US Army.. During my Army career, I was 13E.. I had to make the calculations for each of the 8 artillery guns I was responsible for to hit their target.. (in less than 53 seconds).. and it was NOT an easy task.. Earth rotation.. humidity (moisture), wind speed, elevation.. etc...

I started programming (98% math) around about 1985...

Oh, I forgot to mention I HATE math :/

In the US Army (actually because of my ASFAB score), I didn’t have much choice in what career.. I would have chosen snipe school.. but my math score was too high :/ for what they were asking for at the time.. go figure)

[Colonel_Flagg]

I learned it in basic algebra. MortMan is right on the beam. You’re right, it’s not that difficult. And it’s 288 :)

[Tim n Texas]

exactly. If I was using a pencil/paper I would write it like this:

48
——————— =. 2
2(9+3)

[MortMan]

Except that 135 extended the parenthesis precedence outside the parenthesis, which is a new and novel approach to operator precedence. It is also incorrect.

[Forty-Niner]

Try this:

48
______________ = ?

2(9+3)

2 is correct........

Operationallly you cannot separate the 2 from the parands.

Thus 2(9+3) must be the first operation occurring in the equation.

2(9+3) = 2(12) = 24

48
____ = 2

24

[jda]

what is 1 + 1?

Bureacrat answer:

1 = current level of spending

1+1+1 = proposed level of spending

1+1 = 33% reduction in spending.

Liberlista answer:

Whatever you think it is - there are no absolutes.

[MortMan]

I’m not sure what made you believe that the multiplication is handled before the definition, but I can’t find any new or old rules that are written down to support it.

Care to share?

[tioga]

The answer is 2. It’s pretty simple algebra. Amazing that the two machines give a differing answer, perhaps human error?

[brityank]

I dropped this in WolframAlpha and it too gives the incorrect answer (to my knowledge) of 288.

Like others have stated, the sequence to solve is parenths, multiplication, division, addition, and subtraction in that order - and by that the answer is 2. I sent a followup to WolframAlpha for their explanation.

[GingisK]

Thus, the correct answer is 288.

I thought so, too. However, you and I are automatically inserting the omitted "*", and then performing arithmetic as for computer languages. The rub is that in traditional pencil & paper mathematics, 2X is 2*X with a higher precedence than parenthesis

[RikaStrom]

I’ve never seen a rule that extended the parenthetical precedence outside the parenthesis.

I don't know what to tell you MM, the way I was taught was that if there was a number immediately next to the parenthesis, then that number was to be included in the results from doing the the parenthesis first.

ie:
a(b+c) = (a * (b + c))

I've got to say from watching the discussion, this appears to be a generational educational difference.

[Bikkuri]

Thank you... and for those other programmers out there.. please help us explain.. I am not good a technical writing :p

Bikk

[MortMan]

You are missing my point, FRiend.

The fact that you have put the sum of 9 and 3 below the line means you have added the parenthesis around 2(9+3).

The correct archaic form of this is

__48__ * (9+3)
2

Check the rules. The Wikipedia listing (which I have checked elsewhere) explicitly identifies the placement above or below the horizontal division operator as the same as modern parenthesis.

[RikaStrom]

I suspect those who think the answer is 288 are far younger than those of us who know the answer is 2.

LOL, I think I have to agree with you on that. I wish I had kept my old work books, it would be interesting to scan in a couple of pages to show.

[spunkets]

Re: NOTE: The original eq. is ≠ to:48/(2*12) for reference it's 48*0.5*12. Note the multiplicative factors must commute. That's made possible by the concept of multiplicative inverse(the /sign), which applies to "2" and renders it a factor of 1/2, or 0.5.

"Yes it is."

Show your work.

"How old are you? "

Irrelevant.

[MortMan]

Why did you put the (9+3) below the line? That implies parenthesis around the whole expression 2(9+3), which are missing from the equation.

[MortMan]

Please explain why you put the (9+3) below the line - that is the error in your calculation.

[MortMan]

What rule tells you the 2 and the (9+3) are inseparable?

[BushCountry]

I put the problem in correctly. Google forced the issue and applied it’s logic. The result was shown.

However, I called in the big guns. My son has tutored Calculus, Chemistry and hard sciences at FSU for three years. He attended Emery Riddle in the 9th grade. I asked him to solve the problem. He gave a definitive 288 result.

[Zman516]

The equation written as 48/2(9+3)= is being interpreted by the calculator as one half of 48 (24) times nine plus three (12) = 288

The equations is more accurately written as 48÷2(9+3)=
or, 48 divided by the quantity 2 times 9+3 (24) = 2

I’m sure this has been pointed out many times as I’ve not the time to read thru the whole thread. Sorry.