Posted on 04/12/2011 1:32:09 PM PDT by grundle
Texas Instruments TI-85 says:
48÷2(9+3) = 2
But Texas Instruments TI-86 says:
48÷2(9+3) = 288
You see? That is why math is never the answer to anything. There is nothing stable about it, nor does it ever make any sense. I say do away with math forever. There is no
need for it in a sane world. That is my position since first grade and I have not changed my mind in 71 years, nor will I ever.
It’s simple - one calculator uses the rules of arithmetic and the other uses Congressional rules of arithmetic.
Thanks, Mort and fremont.
She is dead now...it has been many years since grade school. ))
The only thing being distributed is 2(9+3).
You fail.
You had it right the first time.
No, the problem is expressed very clearly. Do the distribution first (which is resolving the parentheses, which everyone agrees must be done first) and you end up with 48 divided by 24 = 2.
Did you view the video at the link I posted? It could not be clearer.
This is from purplemath.com. For all you 288ers, read it and weep:
This next example displays an issue that almost never arises but, when it does, there seems to be no end to the arguing.
Simplify 16 ÷ 2[8 – 3(4 – 2)] + 1.
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
The confusing part in the above calculation is how “16 divided by 2[2] + 1” (in the line marked with the double-star) becomes “16 divided by 4 + 1”, instead of “8 times by 2 + 1”. That’s because, even though multiplication and division are at the same level (so the left-to-right rule should apply), parentheses outrank division, so the first 2 goes with the [2], rather than with the “16 divided by”. That is, multiplication that is indicated by placement against parentheses (or brackets, etc) is “stronger” than “regular” multiplication
“The only thing being distributed is 2(9+3).”
Not in the video link you posted.
If the expression were limited to a single, stand-alone distribution, your obsession with it might matter. However, you ignore the order of operations to arrive at an incorrect answer.
Watch the first 20 seconds of this video to understand how to evaluate the expression in question.
http://www.youtube.com/watch?v=k-VJjfw90jc
Evaluate the operations inside the parens first. Then evaluate div and mult operators from left to right. Finally, evaluate add and subt operators from left to right.
Your answer is hidden by the cotton; count them ;^)
I originally interpreted the expressin as:
48
2(9 + 3)
But, I think it is correctly written as:
| 48 2 |
(9+3) |
Well, I’m absolutely certain the correct answer is between 1 and 300.
Check post #429.
LOL
Did you ignore this part: “parentheses outrank division”?
Go throught the purplemath example and use the same principles and you will see the correct answer is 2.
Does implied multiplication and explicit multiplication have the same precedence on TI graphing calculators?
Implied multiplication has a higher priority than explicit multiplication to allow users to enter expressions, in the same manner as they would be written. For example, the TI-80, TI-81, TI-82, and TI-85 evaluate 1/2X as 1/(2*X), while other products may evaluate the same expression as 1/2*X from left to right. Without this feature, it would be necessary to group 2X in parentheses, something that is typically not done when writing the expression on paper.
This order of precedence was changed for the TI-83 family, TI-84 Plus family, TI-89 family, TI-92 Plus, Voyage™ 200 and the TI-Nspire™ Handheld in TI-84 Plus Mode. Implied and explicit multiplication is given the same priority.
Here are two points of clarification for the names of certain symbols germane to this discussion:
\ - reverse solidus or backslash (NOT division) / - solidus, virgule or slash (division) * - star, splat, asterisk or glob (multiplication)All of these and so much more at Second Amendment Advocate Eric Raymond's famous Jargon File.
A courtesy ping to rdb3 since he likes all this obscure geek stuff and as fellow Linux user encounters the slash quite often as the directory separator -- not like what they use on that other "operating" system. :-)
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