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I'm stumped, whats the missing number (1 Viewer)

TimDoss

Second Unit
Joined
Jun 10, 1999
Messages
298
could be factoring, except for that damn 1
5 = 5x1
10 = 5x2
15 = 5x3
so we have 1, 2, 3
25 = 5x5x1
50 = 5x5x2
then 75 = 5x5x3

This better not be some sick april fools joke.
 

Lee L

Supporting Actor
Joined
Oct 26, 2000
Messages
868
OK, I'm a dumb ass. :b :b :b :b



Hey, I'm only a construction estimator and I deal with adding numbers all day long. ;)


Still can't figure it out though.
 

Keith Mickunas

Senior HTF Member
Joined
Dec 15, 1998
Messages
2,041
I think the "100" answer provided by Tim makes sense. I don't like the answer because its not mathematical in nature. However most of the other solutions proposed are far beyond 4th grade mathematics. This looks like some of that "New Math" crap. They're teaching specific applications of math in the real world, but not how or why it works, which is necessary to understand higher mathematics.

This reminds me of when one of my roommates in college was in a communications class. The teacher started providing math problems like this: 3 + 3 = 6, 11 + 4 = 3, 5 + 9 = 2, 1 + 7 = 8, and so on. She asked what kind of math that was. My roommate said "addition modulus 12" which is obviously correct, well obvious if you know lots of math. The teacher had no clue what that meant and just said it was "clock math".

In that case the answer was wrong because the teacher didn't know much math, and its the same with this series. We look for a mathematical reason, and there isn't one. This most likely comes out of some lesson covered in class, and you have to know the parameters of that to come up with the right answer.
 

Joseph Howard

Stunt Coordinator
Joined
Sep 10, 1997
Messages
227
I must ask a silly question. Does the MISSING number have to be at the END of the sequence?

I see these things all the time and one should not assume the number we need is at the end.

PS.... Try multiplying each number in the sequence with a common factor. It might help.

Dr. Joe
 

Daren Welsh

Supporting Actor
Joined
Jan 16, 2002
Messages
660
My roommate said "addition modulus 12" .... The teacher had no clue what that meant and just said it was "clock math".
LMAO

My main hangup is the 1. Usually when I see a 1 at the beginning of a series I think it involves powers (x^0 = 1) or has something to do with multiple entries (i.e. 1 + 5 = 6, 5 + 10 = 15). Of course I can't find anything useful in that with this problem ....
 

Chris Tsutsui

Screenwriter
Joined
Feb 1, 2002
Messages
1,865
Answer: 100

High performance melt blown filtration Retention Ratings: 0.5, 1, 5, 10, 15, 25, 50, 75, 100, 150 µm Differential Pressures. Every 4th grader knows these numbers if they come from the Cayman Islands.

OR

Cayman Islands Coins:
1¢, 5¢, 10¢, 15¢, 25¢, 50¢ $1
They are a 4th grade class on the Cayman islands so everyone knows that 100 is the answer.
 

Bill Griffith

Supporting Actor
Joined
Jan 8, 2002
Messages
581
Well the teacher made a mistake the sequence is supposed to be as follows.

1, 5, 10, 25, 50, ?

the final answer is $1

Even after she told us the answer she didn't realize she had made a mistake until we asked her to prove it. As soon as she got to the 15 she knew. "well this isn't supposed to be there"

LMAO
 

TimDoss

Second Unit
Joined
Jun 10, 1999
Messages
298
Maybe she needs to be in the fourth grade instead of teaching it.

And I agree with Scott... she deserves pain for this.
 

Brian Perry

Senior HTF Member
Joined
May 6, 1999
Messages
2,807
While it's important to teach kids about money, I think it's a poor choice for a teacher to present such a question to kids in a math quiz. The numbers do not represent a sequence, per se, but rather a collection of coin values that were arbitrarily chosen as practical by the government.
 

MickeS

Senior HTF Member
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Jul 24, 2000
Messages
5,058
:laugh:

Bill, please tell that teacher about the sleepless hours she gave us. :)

/Mike
 

Keith Mickunas

Senior HTF Member
Joined
Dec 15, 1998
Messages
2,041
Bill, why are you taking a 4th grade math class? I thought maybe this was your kids, but it looks like you've already been to class this morning.
 

BrettB

Senior HTF Member
Joined
Feb 1, 2001
Messages
3,019
I imagined that the HTF membership was diverse but I had no idea that 4th graders hung out here. ;)
 

Malcolm R

Senior HTF Member
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Feb 8, 2002
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25,139
Real Name
Malcolm
Even after she told us the answer she didn't realize she had made a mistake until we asked her to prove it.
No wonder we're raising a generation of dumbasses. The dumbasses from the last generation are educating them. And "clock math"? :rolleyes

She could have saved a little face by saying the 15 represents the value of a Canadian Quarter in the U.S. :D
 

Mark Zimmer

Senior HTF Member
Joined
Jun 30, 1997
Messages
4,318
And what about the formerly-used but now defunct two and three cent coins? Has this woman no sense of history??? ;)
 

Bill Griffith

Supporting Actor
Joined
Jan 8, 2002
Messages
581
Even after she told us the answer she didn't realize she had made a mistake until we asked her to prove it. As soon as she got to the 15 she knew. "well this isn't supposed to be there"
My life would be easier if I were in the fourth grade.

We asked her. It is possible for a grownup to speak with the teacher.

While I'll be the first to give teachers some slack (everyone makes mistakes) since there grossly underpaid.

I will disagree with the the way they are teaching kids these days and the way some teachers would probably fail the same tests they give thier students.
 

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