Math for cf.neters

[thisnumbersdisconnected]

It's humiliating for me to admit I majored in math... 25 years ago. As I recall, without the functions grouped like (4 x 4), you simply calculate this in the order that the functions come.

I say it's 320.

That's exactly right. There are those that claim that the functions have to be performed by the "My Dear Aunt Sally" formula regardless of whether the functions are grouped or not. Wrong! It is a hard and fast rule of mathematics that without the groupings, you go through the process function by function. I've got an aviation engineering degree (which I find to be totally useless these days), force-fed me by the Army, that says so.

Dear CF'er math club members: You're trying to solve the problem under rules given you by high school teachers and collegiate basic math instructors. Please read this carefully: They are wrong. Engineers given this formula would arrive at the correct answer of 320.

 

[tim-from-pa]

That's exactly right. There are those that claim that the functions have to be performed by the "My Dear Aunt Sally" formula regardless of whether the functions are grouped or not. Wrong! It is a hard and fast rule of mathematics that without the groupings, you go through the process function by function. I've got an aviation engineering degree (which I find to be totally useless these days), force-fed me by the Army, that says so.

Dear CF'er math club members: You're trying to solve the problem under rules given you by high school teachers and collegiate basic math instructors. Please read this carefully: They are wrong. Engineers given this formula would arrive at the correct answer of 320.

OK, then it's Please Excuse my dear aunt Sally.

But there's no parenthesis in the equation, nor exponents so I dropped the PE.

So, what's the point in writing parenthesis if one can choose to do operations in any way they choose? Maybe I like to do the addition and subtraction first, or maybe from right to left if I'm Jewish. So one can then get any number of answers depending on the order they do their operations if there's no rules.

If one does things simply from left to right, as with a calculator, then one is effectively adding where they think the parenthesis should go (i.e. in order)

Thus, a math convention had to be adopted to erase all confusion.

20 is the correct answer. If you want 320 as an answer, then write the equation the proper way using parenthesis to get it.

 

[WIP]

20.

Order of operations multiply first, then add and subtract.
(4x4)+(4x4)+4-(4x4) = 16+16+4-16 = 20

 

[Classik]

Options so far by 7 members: 68 by 1 member*****320 by 3 members*****20 by 6 members

Options so far by 12 members: 68 by 1 member*****320 by 4 members*****20 by 7 members

 

[WIP]

Maybe this will help.

View attachment 2897

 

[tim-from-pa]

Options so far by 12 members: 68 by 1 member*****320 by 4 members*****20 by 7 members

And here's something else that will help:

http://en.wikipedia.org/wiki/Order_of_operations

This is a well established convention not to keep school-age kids straight, but something that mathematics and computers use.

We are not debating fuzzy math or theology here, but a straightforward mathematical expression which is absolute, so taking polls is no indicator of the correct answer--- no voting in mathematics.

If some people can't accept the right answer, so be it, but if I was a moderator I'd lock this thread if it became too contentious because to debate over an absolute is totally ludicrous.

 

[evenifigoalone]

I'm so confused...

If I fail my next math test I'm blaming you guys.

 

[Eugene]

4x4 + 4x4 + 4 x 4 +4 - 4x4 =

Something that has been affecting my thinking is the sum of zero as the result of 4x4 - 4x4. Anything multiplied by zero equals zero.

Thus 4x4 + 4x4 + 4 times zero equals zero. The answer is zero.

Thank you - Thank you. I'd like to thank the commission of sciences, my mother . . .

 

[thisnumbersdisconnected]

So, what's the point in writing parenthesis if one can choose to do operations in any way they choose?

That's not what I said. I said, if there are parentheses in the equation, it is indicative of the order of operations not being in order of appearance, but in order of importance as established by the parentheses. If there are no parentheses, then you work from left to right, solving each mathematical function in the order written. That's all there is to it.

 

[Classik]

4x4 + 4x4 + 4 x 4 +4 - 4x4 = Something that has been affecting my thinking is the sum of zero as the result of 4x4 - 4x4. Anything multiplied by zero equals zero. Thus 4x4 + 4x4 + 4 times zero equals zero. The answer is zero.

Thank you - Thank you. I'd like to thank the commission of sciences, my mother . . .

Ukulele! Wooooow! Gracious Goodness.

 

[Classik]

Options so far by 12 members: 68 by 1 member*****320 by 4 members*****20 by 7 members

Options so far by 13 members: 68 by 1 member*****320 by 4 members*****20 by 7 members*****0 by 1 member

 

[tim-from-pa]

.... If there are no parentheses, then you work from left to right, solving each mathematical function in the order written. That's all there is to it.

Nope. Let's do this again, it's left to right using PEMDAS, that's the mathematical/computer world convention.

Only on a religious forum can something so precise as mathematics be subject to interpretation. :toofunny : Geeez.

 

[thisnumbersdisconnected]

Nope. Let's do this again, it's left to right using PEMDAS, that's the mathematical/computer world convention.

Not in the world of engineering, and I'm 99.99999% certain that world isn't any different than other higher mathematics. What students are being taught in middle- and high school is contrary to the way the rules of math are followed in the real world where math actually matters.

 

[Classik]

And the answer is....;)

 

[Deborah13]

Engineer forum....same type of problem.

http://www.eng-tips.com/viewthread.cfm?qid=328291

 

[Deborah13]

What unreal about this problem is all the 4s.

Multiplication and addition are both communitive therefore they can be arranged in different orders and still have the same answer, correct? UNLESS you don't use PEMDAS.

4*2+3=11 2*4+3=11 3+4*2=11 3+2*4=11 using PEMDAS

4*2+3=11 2*4+3=11 3+4*2=14 3+2*4=20 using left to right three different answers??

Math the universal language.

 

[Classik]

Math is quite a crazy thing.:toofunny

 

[thisnumbersdisconnected]

When genius is required, that requires an engineer. And you have the double bonus in that I'm in my second career now as an addictions counselor. So not only can I design you an airframe, I can help make sure that using it is the only high you get. :toofunny

 

[Claudya]

I'm with the 20 faction.

Multiplication precedes addition, so

4*4 +4*4 +4 -4*4=
16 + 16 +4 -16 =
32 +4 -16 =20

another way to solve it:

(4*4) +(4*4) +4 -(4*4) = x /added parantheses to make the structure of the equation easier to see
(4*4) +(4*4) -(4*4) +4 = x /as Deborah said, the order of the terms can be changed
(4*4) +(4*4) -(4*4) = x - 4 /subtracted 4 on both sides of the equation
(4*4) = x - 4 /because (4*4) - (4*4) is 0, so two of those terms eliminate each other
16 = x - 4
x = 16 + 4

 

[Classik]

4 :bigfrown