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Mother Tree
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This one nearly beat me.. ;)

 
pollinator
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The meme is correct.  I don't believe it.  the answer is 120.
 
gardener
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Yup 120. I can't believe how many times these things are wrong.
 
Burra Maluca
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It's not wrong!
 
Todd Parr
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Burra was right Shawn, and we are wrong. 
 
Burra Maluca
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Nope, no one is saying anyone is wrong.  That would be against the rules now, wouldn't it...
 
Todd Parr
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Burra Maluca wrote:Nope, no one is saying anyone is wrong.  That would be against the rules now, wouldn't it...



Shawn "misspoke".  I was just wrong.
 
Shawn Klassen-Koop
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Am I missing some kind of trickery or is it not asking for the answer to 230 - 220 x 1/2? Because if it is asking that then I'm going to stick to my previous answer.
 
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Nice one. (And everyone is correct, as 5! = factorial(5) = 120)
But a bit mean… using factorial where one expects punctuation.
 
Shawn Klassen-Koop
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Thank you Sebastian for pointing it out. Yes this was trickery. Yes this was a good one. Thanks Burra.
 
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I got it but in an incorrect way I guess because it seems obvious...

230-220 equals 10 then times 1/2 equals 5.

How were we supposed to solve? 

I don't have a clue what 

using factorial where one expects punctuation.

means?

haha...now it's bugging me that it says 'most people won't believe it' ....what am I missing?
 
Todd Parr
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Judith Browning wrote:I got it but in an incorrect way I guess because it seems obvious...

230-220 equals 10 then times 1/2 equals 5.

How were we supposed to solve? 

I don't have a clue what 

using factorial where one expects punctuation.

means?

haha...now it's bugging me that it says 'most people won't believe it' ....what am I missing?



Judith, the correct way to solve the problem is 220 times 1/2 equals 110.  230-110=120.  In equations, you have to multiply before you subtract, so you have to multiply the 220 x 1/2 before you subtract.  5! is 5x4x3x2x1 which is also 120.  5! is 5 factorial.

I just re-read that, and I hope my explanation didn't make it more confusing than it already was    Bottom line is the correct answer is 120.  120 is equal to 5!
 
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Todd Parr wrote:

Judith Browning wrote:I got it but in an incorrect way I guess because it seems obvious...

230-220 equals 10 then times 1/2 equals 5.

How were we supposed to solve? 

I don't have a clue what 

using factorial where one expects punctuation.

means?

haha...now it's bugging me that it says 'most people won't believe it' ....what am I missing?



Judith, the correct way to solve the problem is 220 times 1/2 equals 110.  230-110=120.  In equations, you have to multiply before you subtract, so you have to multiply the 220 x 1/2 before you subtract.  5! is 5x4x3x2x1 which is also 120.  5! is 5 factorial.



So it's all about the exclamation point! I was taking art and music classes instead of any advanced math...this is a new concept that will probably be gone from my head again soon   thanks!
 
Burra Maluca
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Here's a video to introduce the idea, and importance, of order of operations for anyone who hasn't encountered it before.

 
Sebastian Köln
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The notation for factorials is … well it works, as long as it is never mixed with text.
But this generally applies to mathematics in general, and anyone doing serious work in that area will make absolutely sure mathematics and text are set in different fonts.
So it should read

[…] but the answer is: (5!)



The factorial is defined as:
0! = 1
1! = 1
n! = n · (n-1)!

which means: 5! = 5 · 4! = 5 · 4 · 3! = 5 · 4 · 3 · 2! = 5 · 4 · 3 · 2 · 1! = 5 · 4 · 3 · 2 · 1 = 120
 
Burra Maluca
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Or if your eyes glaze over trying to read that, try this instead - mathis is fun - factorials
 
master steward
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Well done! I'd completely forgotten the factorial thing, so the exclamation point did not register at all.

Even if the '5!' was separated in parentheses, or by a different font, it probably wouldn't have helped me. Order of operations is still normal for me, though apparently I've lost loads of other math knowledge.  :-/

 
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Sneaky of them but it also requires observation skills that permies are supposed to have.

The answer the wrong way = 5  which would be written (230-220) x1/2 =
The answer the right way =120 which is written 230-220 X 1/2 = or it could be written 230 - (220 x 0.5) =  

Math is one of the "if you don't use it, you loose it" high school skills.
 
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my explanation.
5fattoriale.png
[Thumbnail for 5fattoriale.png]
 
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