Simple Math

[PenMan1]

Everyone Pities My Dear Aunt Sally

Exponents,Parenthesis,Multiplication,Division,Addition,Subtraction


X=20

Not quite

Please Excuse My Dear Aunt Sally.

Parenthesis take precedence over exponents

If your Aunt had been named Sarah, instead of Sally no one would have to "pity or excuse Sarah......now, Sally on the other hand, could be a real P.E.M.D.A.S., LOL!

We had a teacher in school named Sally. She went nuts in the middle of the school year. The math teacher changed the mnemonic to Sarah

 

[GaryMGg]

I can still do some math in my head! :biggrin:

20

* and / get precedence over + and - (barring parens).

 

[CabinetMaker]

Okay simple math question for you guys.

Try not to look at the answers from others before posting.

4*4+4*4+4-4*4=X

What is X?

X=20

 

[Russianwolf]

I have seen several of these math problems being posted on FB. Generally all order of operations.

amazing how many people have forgotten the simple stuff ain't it.

Yep, the answer is 20.

 

[triw51]

320

 

[Mason Kuettel]

20-will be teaching that on Monday!

 

[jking]

20 ...

 

[jking]

I have seen several of these math problems being posted on FB. Generally all order of operations.

amazing how many people have forgotten the simple stuff ain't it.

Yep, the answer is 20.

Unfortunately, so have some of the teachers. A friend of mine got in trouble with his son's teacher over order of operations. The teacher wasn't teaching the kids order of operations and one of their homework problems had mixed operations in it. When his son told him he didn't understand how of solve the problem, my friend looked at it and explained the order of operations. Son comes home from school the next day and tells his dad he was wrong and that he failed the assignment. My friend ended up calling to talk to the teacher and is told that isn't the way she explained it to the class and she'd appreciate it if he'd "leave the teaching to us". He was not happy, but, didn't push it farther because he thought she'd end up punishing his son if he did. I would have raised a major stink about it.

 

[Smitty37]

Okay simple math question for you guys.

Try not to look at the answers from others before posting.

4*4+4*4+4-4*4=X

What is X?

16+16+4-16=20 X=20

 

[Smitty37]

Everyone Pities My Dear Aunt Sally

Exponents,Parenthesis,Multiplication,Division,Addition,Subtraction


X=20

Nope...Parenthesis, Exponents, Multiplication, Division, Addition, Subtraction because there can be an exponent outside the parenthesis that acts on the result of the operation within the parenthesis. i.e. (2a + 3a)Exp.2

 

[Smitty37]

I have seen several of these math problems being posted on FB. Generally all order of operations.

amazing how many people have forgotten the simple stuff ain't it.

Yep, the answer is 20.

Unfortunately, so have some of the teachers. A friend of mine got in trouble with his son's teacher over order of operations. The teacher wasn't teaching the kids order of operations and one of their homework problems had mixed operations in it. When his son told him he didn't understand how of solve the problem, my friend looked at it and explained the order of operations. Son comes home from school the next day and tells his dad he was wrong and that he failed the assignment. My friend ended up calling to talk to the teacher and is told that isn't the way she explained it to the class and she'd appreciate it if he'd "leave the teaching to us". He was not happy, but, didn't push it farther because he thought she'd end up punishing his son if he did. I would have raised a major stink about it.

She probably has an old "Reverse Polish Notation" calculator that performs each function as it is entered - hence simply from left to right which would give a very different answer which would be totally incorrect. I had this happen once with one of my kids, and when the teacher told me she had explained it differently - I told her that my kid's paper had the correct answer no matter how she had explained it. When she implied that she was the teacher - I told her that my degree was just as good as hers and that I had passed mathematics through linear differential equations and the the rules of algebra were always the same.

 

[Russianwolf]

I have seen several of these math problems being posted on FB. Generally all order of operations.

amazing how many people have forgotten the simple stuff ain't it.

Yep, the answer is 20.

Unfortunately, so have some of the teachers. A friend of mine got in trouble with his son's teacher over order of operations. The teacher wasn't teaching the kids order of operations and one of their homework problems had mixed operations in it. When his son told him he didn't understand how of solve the problem, my friend looked at it and explained the order of operations. Son comes home from school the next day and tells his dad he was wrong and that he failed the assignment. My friend ended up calling to talk to the teacher and is told that isn't the way she explained it to the class and she'd appreciate it if he'd "leave the teaching to us". He was not happy, but, didn't push it farther because he thought she'd end up punishing his son if he did. I would have raised a major stink about it.

I would have done the exact thing that my mother did when I wanted to take french III and was told that not enough students had signed up. Called the Superintendent.

granted I had to drive between schools during lunch, but I had French III on my transcript.

I'd be having a sit down with her at the very least.

 

[PenMan1]

Smitty:
Funny you should mention RPN, many of the better HP calculators made today STILL have a "button" to do this.

 

[Smitty37]

memory

Smitty:
Funny you should mention RPN, many of the better HP calculators made today STILL have a "button" to do this.

I still remember this because we had to rewrite a lot of problems that we wanted to do so we could get the correct order of operations...It was a pain in the toosh.

 

[jking]

I doubt an elementary school teacher would have an RPN calculator. I think she just didn't want to get into the order of operations, yet. Unfortunately, all that will do is confuse the kids later when they learn they've been doing their math wrong.

RPN calculators aren't hard to use, you just have to think differently when using them. The one I had through college & my first several years out of college allowed you to enter equations. It also stored several previous entries so you could go back & repeat the same basic calculation with different numbers. My current one does this too, but, it's not RPN.

 

[LagniappeRob]

RPN isn't as entered (as in left to right). It's Operands before Operators and involves the use of a stack.

For example to simulate the same equation (including compensating for OOO) in RPN would be:

                Stack Pos  A   B   C  D  
4                   Stack:  4
4                   Stack:  4  4
*                   Stack:  16
4                   Stack:  4  16
4                   Stack:  4  4  16
*                   Stack:  16  16
+                   Stack:  32
4                   Stack:  4  32
+                   Stack:  36
4                   Stack:  4  36
4                   Stack:  4  4  36      
*                   Stack:  16  36
-                   Stack:   20
=

It would be clearer if it wasn't all 4's. I still use RPN on a lab system to this day.

There... that should help with what's going on. Entering data puts in on the LIFO stack. Operators always work on the last 2 items on the stack, and the results become 1 item on the stack. So 4, 4, * = 4*4 and 16 goes onto the last place in the stack.

 

[Smitty37]

RPN isn't as entered (as in left to right). It's Operands before Operators and involves the use of a stack.

For example to simulate the same equation (including compensating for OOO) in RPN would be:

                Stack Pos  A   B   C  D  
4                   Stack:  4
4                   Stack:  4  4
*                   Stack:  16
4                   Stack:  4  16
4                   Stack:  4  4  16
*                   Stack:  16  16
+                   Stack:  32
4                   Stack:  4  32
+                   Stack:  36
4                   Stack:  4  36
4                   Stack:  4  4  36      
*                   Stack:  16  36
-                   Stack:   20
=

It would be clearer if it wasn't all 4's. I still use RPN on a lab system to this day.

There... that should help with what's going on. Entering data puts in on the LIFO stack. Operators always work on the last 2 items on the stack, and the results become 1 item on the stack. So 4, 4, * = 4*4 and 16 goes onto the last place in the stack.

Don't you also have to hit enter between operands? My last several calculators used algebraic notation for equation entry so I don't remember too much about RPN.