So, according to your description, the following expression

X = 64 / 4 * 8

should yield a value of 2.

No. I said "...as they appear." and 64/4 appears first.

You then say Multiplication as they appear. That means it becomes

X = 64 / (4 * 8)

The multiplication appears after the division.

But the universally (as far as I am aware) agreed upon rules for order of operations state that multiplication and division are of the same precedence and are left associative and that, likewise, addition and subtraction are of the same, albeit lower, precedence and also left associative.

Thus

X = 64 / 4 * 8 = (64 / 4) * 8 = 128

That's what I would expect and that's what I stated. The "...as they appear." means exactly that.

 

No. I said "...as they appear." and 64/4 appears first.




The multiplication appears after the division.



That's what I would expect and that's what I stated. The "...as they appear." means exactly that.

Here's what you said: Parentheses first, Exponents, Multiplication as they appear, Divisions as they appear, Additions and Subtraction as they appear.

If you don't mean that ALL multiplications are done before ANY divisions, then you also don't mean that ALL multiplications and divisions are done before ANY additions and subtractions.

If you claim that your rule has you do a division before a multiplication if it appears first, then your rule also says that you do additions and subtractions before multiplications or divisions if they appear first.

You can't have it both ways.

What you should have said was: Parentheses first, Exponents, Multiplication and Divisions as they appear, Additions and Subtraction as they appear.

 

There was a TV comedian who would have said to you: "You don't get out enough!"

Almost certainly true -- but since I'm not big on having my calculator do my thinking for me, I don't invest a lot in getting one that will do so.

The 25+ year old HP48 calculator could track units and a number of its descendants still do. Here's the TS's calculation as he typed it in, shown on my HP50G calculator. Sorry for the slightly blurry images:

How well does it recognize derived units?

For instance, if you were to enter 1 Ω + 10 V / 2 A, would it recognize this and evaluate it as 6 Ω?

If you enter 10 H * 50 A / 2 s will it evaluate to 250 V?

Can you define new units and their relationships to existing units?

Even though the calculator might allow you to use units (which is wonderful), unless it forces you to use units (by making you explicitly indicate that a pure number is dimensionless) then I suspect that the units utility is virtually never utilized.

 

Here's what you said: Parentheses first, Exponents, Multiplication as they appear, Divisions as they appear, Additions and Subtraction as they appear.

If you don't mean that ALL multiplications are done before ANY divisions, then you also don't mean that ALL multiplications and divisions are done before ANY additions and subtractions.

If you claim that your rule has you do a division before a multiplication if it appears first, then your rule also says that you do additions and subtractions before multiplications or divisions if they appear first.

You can't have it both ways.

What you should have said was: Parentheses first, Exponents, Multiplication and Divisions as they appear, Additions and Subtraction as they appear.

There's not a lot of mystery here. You work out anything inside of a grouping symbol. Then work out exponents. Then do any multiplication AND/OR division as it comes along, then any addition AND/OR subtraction as it comes along. That's the meaning of "as they appear." Multiplication and division take precedence over addition and subtraction, but not each other.

 

There's not a lot of mystery here. You work out anything inside of a grouping symbol. Then work out exponents. Then do any multiplication AND/OR division as it comes along, then any addition AND/OR subtraction as it comes along. That's the meaning of "as they appear." Multiplication and division take precedence over addition and subtraction, but not each other.

But that is NOT any reasonable interpretation of what you wrote! You grouped multiplication separately from division but grouped addition and subtraction together.

Ask your self why, according to your quote, multiplication and division take precedence over addition and subtraction. The ONLY thing that can indicate that this is the case is because addition and subtraction are in a later clause with their own mutual "as they appear" phrase. Fine. I agree. But then according to that, multiplication takes precedence over division because it is in a later clause exactly the same way and each has its own "as they appear" phrase. You have to interpret it according to what you wrote actually means, not according to what you wanted it to mean.

 

Almost certainly true -- but since I'm not big on having my calculator do my thinking for me, I don't invest a lot in getting one that will do so.

The idea is not for the calculator to do the thinking, but rather to take care of the tedium of evaluating a complicated expression with units involved. The small homework problems that we see in this forum can easily be done by hand. But suppose you have a tenth degree polynomial from a filter design. Using modern computing hardware to take care of the drudgery of the algebra doesn't constitute letting a machine do your thinking.

The thing I was needling you about wasn't that you don't have one, but that you didn't know they exist.

How well does it recognize derived units?

For instance, if you were to enter 1 Ω + 10 V / 2 A, would it recognize this and evaluate it as 6 Ω?

If you enter 10 H * 50 A / 2 s will it evaluate to 250 V?

Can you define new units and their relationships to existing units?

It can do all these things. With a button push the 250 V becomes 250 (kg*m^2)/(A*s^3)

Even though the calculator might allow you to use units (which is wonderful), unless it forces you to use units (by making you explicitly indicate that a pure number is dimensionless) then I suspect that the units utility is virtually never utilized.

I think your experience on the AAC homework forum has made you pessimistic.

From what new users said on the old HP forum when the HP48 first came out with this capability, it was welcomed (and used) by students just learning to use units and they didn't need to be forced to use them. Whether they continued to use the feature later in their career I couldn't say.

 

But that is NOT any reasonable interpretation of what you wrote! You grouped multiplication separately from division but grouped addition and subtraction together.

Ask your self why, according to your quote, multiplication and division take precedence over addition and subtraction. The ONLY thing that can indicate that this is the case is because addition and subtraction are in a later clause with their own mutual "as they appear" phrase. Fine. I agree. But then according to that, multiplication takes precedence over division because it is in a later clause exactly the same way and each has its own "as they appear" phrase. You have to interpret it according to what you wrote actually means, not according to what you wanted it to mean.

I apologize. Next time, I will have you proofread what I write to catch the small semantic variances. Can you check it for proper punctuation too? I sometimes leave out commas, and you can imagine how bad that would be in a sentence like "I helped my uncle, Jack, off a horse." The humanity.

 

I apologize. Next time, I will have you proofread what I write to catch the small semantic variances. Can you check it for proper punctuation too? I sometimes leave out commas, and you can imagine how bad that would be in a sentence like "I helped my uncle, Jack, off a horse." The humanity.

Sloppy writing -- which we ALL do on a regular basis -- is normally not a big issue. But hopefully you can see that it IS an issue when you are trying to communicate very specific information that needs to be conveyed precisely. The very fact that you are trying to explain order of operations to someone that doesn't have a good handle on them means that they need that information to be given correctly and unambiguously.

And a worse sentence is, "We are going to stop and eat, John, before we go any further."

 

You might want to review your equations. You have a typo there.

I am sorry
should be: Vo = 8V * 1ohm/(6ohm + 1ohm) = 8V*1Ohm/7Ohm=1,142857142857V
WBahn, many thanks for commenting!