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"5 factorial" is not a solution; it is simply representing the answer (120) as a different equation. If you were set a problem in a mathematics test
300 - 0.5 x 150
and answered that it is 450 / 2, the teacher would be justified in marking it incomplete because it has not been reduced to the simplest terms.
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows.
-- 6079 Smith W.
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My college math professor always told us to leave the simplification to the accountants, at least when it came to tests. No time for that.
He was a great person. He later became the grad student ombudsman after putting up with us (rowdy undergrads) for three straight semesters!
RIP
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I thought about that...but who provides answers as a factorial?
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I think it was meant as a riddle rather than something that actually happened.
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Sometimes I'm just being a little bit too literal.
Daniel's answer above suggests we're both on the same page on this one.
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Yeah, you're both on the AR page.
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Hey, I resemble that!
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows.
-- 6079 Smith W.
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Bernoulli?
"In testa che avete, Signor di Ceprano?"
-- Rigoletto
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A statisticus / mathematician will provide answers as factorial as often numbers are too big to write down.
E.g. 5! is quite easy but 7000000000! is huge. Assuming the world population is 7000000000, 7000000000! is approximately the number of ways you can put their names in a list. As there are people with the same name the number is actually less but still huge.
There are even statistic problems where numbers like n!! (n factorial factorial *) are used which can be even "bigger than huge".
*) besides "n factorial factorial", there exist "n double factorial" which is n x (n-2) x (n-4) ... x 1)
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Interesting. Never knew that anyone ever used factorials other than as, shall I say, a "mathematically interesting" thing and then moving on.
When it comes to extremely large (or small) numbers, I always understood that the standard was to use powers of 10, for example, googling for the weight of the earth, the result is expressed as 5.972x10^24 kg.
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Yup, the scientific notation is far more often used (even wrote an Arduino "lib" for it).
It has become handy in e.g. physics and the national debt
Factorials, permutations and combinations are used a lot in (discrete) simulations e.g. for calculating chances of something happening. But it is true that people will often translate a chance of 1 in 100! as "will never happen"
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rob tillaart wrote: and the national debt
That hurt.
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You are wrong, the teacher is right.
The order of precedence in mathematical operations is (mnemonic PEMDAS):
Parentheses
Exponentiation
Multiplication & Division
Addition & Subtraction
If two operations have the same precedence, they are evaluated from left to right. Your problem may be rewritten as 230 - (220 x 0.5), the answer to which is obviously not 5.
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows.
-- 6079 Smith W.
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3! - 1
I think you'll find
It's curious - nearly everyone I know was taught BODMAS - its the same as PEDMAS, but B=Brackets, O="of". PEDMAS is probably better. Also the great Indian chief "SOH-CAH-TOA". I wonder if they still teach the latter in schools.
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I hadn't heard of PEDMAS before; I'm guessing it's some kind of Hollywood holiday.
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Rather than the Indian chief, we were taught the great Welsh anthem:
Sons of Harlech
Come and Harken
To our Anthem
A geographic thing, I suppose. We were 50 miles from Wales but several thousand from the Indians.
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You write "the answer to which is obviously not 5". Nobody ever said that. The OP sais that he "announced that the answer was 5!". Do you see the difference? The exclamation mark. The answer is 5! (five factorial) and 5!=5*4*3*2*1=120 so 5! is the correct answer
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Please don't repost if your comment does not appear immediately: both of these went to moderation and required a human being to review them for publication. In order to prevent you being kicked off as a spammer, both had to be accepted, and then I have to clean up the spares. Have a little patience, please!
I've deleted the other version.
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
AntiTwitter: @DalekDave is now a follower!
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Note that he said "5!", not "5". He might have given it away too big a clue if he had ended his sentence properly with a period like "...I said the answer is 5!."
Good nerdy riddle.
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Daniel Pfeffer wrote: PEMDAS
I was taught "Please excuse my dear aunt sally".
Or
"Pizza everyone!, my diet already started."
Brent
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He is not wrong. You just didn't see the entire answer in your brain. The exclamation point is there for a reason.
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