Is this correct?

C

cruz33

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THE PROBLEM:

Determine the value of X so that 7X345417803 is a validmoney order identification number. The last number “3” is the error detector number.


THE ANSWER:

Sum of the first ten digits is:
7+3+4+5+4+1+7+8+0 = 39

39, when divided by 9 give you the remainder of 3

9 x4, is 36
36 +3 equals 39
(39 = 9 x 4 + 3)

So X= 0
 
cruz33 said:
Determine the value of X so that 7X345417803 is a validmoney order identification number. The last number “3” is the error detector number.
Click to expand...
Lacking any information on how the money-order identification numbers are constructed, I see no way to proceed. You appear to be doing... something. Were you given additional information which was not included within your post?

Thank you. ;)
 
stapel said:
Lacking any information on how the money-order identification numbers are constructed, I see no way to proceed. You appear to be doing... something. Were you given additional information which was not included within your post?

Thank you. ;)
Click to expand...

Nope, I don't have any more info, that was the question. This is the problem: I have to find what number X represents in order for this money-order number to be correct. I am using here the division by 9 scheme, so the sum of the first 10 digits needs to be divided by 9 and the remainder needs to be the last number of the money-order identification number which in this case is 3. Does this extra info help? Thank you for trying to help!
 
cruz33 said:
Nope, I don't have any more info, that was the question. This is the problem: I have to find what number X represents in order for this money-order number to be correct. I am using here the division by 9 scheme, so the sum of the first 10 digits needs to be divided by 9 and the remainder needs to be the last number of the money-order identification number which in this case is 3. Does this extra info help? Thank you for trying to help!
Click to expand...
This problem is weird.

What stapel was asking you was what you just gave. Check digits are constructed using a fixed procedure (sometimes called an algorithm). To check the check digit, you have to know what the algorithm is. This algorithm, however does not give a unique answer so maybe you described it incorrectly.

If you described it correctly, X = 0 is one right answer but X = 9 is also a right answer.

When you add up the nine known digits, you get 39. If the unknown X is 0, the sum of the digits is 39 + 0 = 39, and the remainder when 39 is divided by 9 is 3. If the unknown X is 9, the sum of the digits is 39 + 9 = 48, and the remainder when 48 is divided by 9 is also 3.
 
JeffM said:
This problem is weird.

If you described it correctly, X = 0 is one right answer but X = 9 is also a right answer.
Click to expand...

It's not so much weird as tricky, Jeff. An attribute of this mod9 method is that a check digit generated thusly won't detect a swap of 9 with 0, or vice versa. (It also won't detect transposition errors.) Not a perfect system, in other words.

X can be either 9 or 0.

Maybe that discovery is the point of the exercise, or maybe either number by itself will be accepted as correct. The Contemporary Math courses that I've seen jump all over the place, touching only lightly on various applications of patterns and algorithms in the current age...
 
mmm4444bot said:
It's not so much weird as tricky, Jeff. An attribute of this mod9 method is that a check digit generated thusly won't detect a swap of 9 with 0, or vice versa. (It also won't detect transposition errors.) Not a perfect system, in other words.

X can be either 9 or 0.

Maybe that discovery is the point of the exercise, or maybe either number by itself will be accepted as correct. The Contemporary Math courses that I've seen jump all over the place, touching only lightly on various applications of patterns and algorithms in the current age...
Click to expand...
Mark

Thank for the information. I'd never heard of Contemporary Math, and it sounds like one of those things Pope warned against:"a little knowledge is a dangerous thing; drink deep or touch not." As for mod 9 check digits, I would not be too worried about the failure to distinguish 9 from 0 because those two digits are far separated on a key pad, but the inability to catch transposition errors is a huge weakness. Out of balance by y; if y / 9 is an integer, you may well have a transposition. Old trick of bookkeepers.
 
Denis said:
This is the one used where I was employed:

Account number followed by check digit C
1 2 3 4 5 6 7 C
7 1 3 7 1 3 7
7 2 9 8 5 8 9 = 48
48 MOD 10 = 8
C = 10 - 8 = 2

Have fun figuring it out...

Account number 1 would be 17.
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You were employed?
 
Other than for entertainment purposes, I don't pay much attention to Popes. ;) (Like Cobert and Stewart, was somewhat disappointed to see Benedict quit...)

The Contemporary Math courses that I've dealth with were "dead-end" courses, designed primarily for liberal-arts students (as well as the mathematically unmotivated) who need to sit through a few math credits, to satisfy some degree requirement. Taking one of these courses would be more like watching a documentary than preparing for subsequent studies. (My opinion)

@cruz33: you don't realize it, but using division and remainders to deduce information about numbers is a big part of a math subject known as "modular arithmetic". Your class probably doesn't go deep enough, to get into actual terminology. Cheers!
 
good observation

JeffM said:
This problem is weird.

What stapel was asking you was what you just gave. Check digits are constructed using a fixed procedure (sometimes called an algorithm). To check the check digit, you have to know what the algorithm is. This algorithm, however does not give a unique answer so maybe you described it incorrectly.

If you described it correctly, X = 0 is one right answer but X = 9 is also a right answer.

When you add up the nine known digits, you get 39. If the unknown X is 0, the sum of the digits is 39 + 0 = 39, and the remainder when 39 is divided by 9 is 3. If the unknown X is 9, the sum of the digits is 39 + 9 = 48, and the remainder when 48 is divided by 9 is also 3.
Click to expand...

Good observation JeffM It is true, 9 could also be the X cause the remainder is also 3! Thanks for that extra info! You guys are awesome!
 
"that discovery is the point of the exercise....."

mmm4444bot said:
It's not so much weird as tricky, Jeff. An attribute of this mod9 method is that a check digit generated thusly won't detect a swap of 9 with 0, or vice versa. (It also won't detect transposition errors.) Not a perfect system, in other words.

X can be either 9 or 0.

Maybe that discovery is the point of the exercise, or maybe either number by itself will be accepted as correct. The Contemporary Math courses that I've seen jump all over the place, touching only lightly on various applications of patterns and algorithms in the current age...
Click to expand...

Yes, you are right! After reading your comment I went back to my textbook because I remember reading something like that and what you said its exactly what the book says about how some numbers (like 0 and 9 in this case) can be entered incorrectly and this is why these division by 7/9 schemes are used to spot errors. Thanks for all the information you have given me; you have been a great help!
 
really grateful!

The Contemporary Math courses that I've dealth with were "dead-end" courses, designed primarily for liberal-arts students (as well as the mathematically unmotivated) who need to sit through a few math credits, to satisfy some degree requirement. Taking one of these courses would be more like watching a documentary than preparing for subsequent studies. (My opinion)

@cruz33: you don't realize it, but using division and remainders to deduce information about numbers is a big part of a math subject known as "modular arithmetic". Your class probably doesn't go deep enough, to get into actual terminology. Cheers![/QUOTE]

I respect your opinion about this course, as a matter of fact I agree with you, it is a "dead-end" course! I am taking this course because I HAVE to take it not because I want to; my field of studies and work has nothing to do with math, and this is why I think I struggle so much with it. But, good thing for people like all of you that are so kind and help others understand these concepts! Thanks again for all your help! By the way, I have 2 more weeks worth of mathematical problems, can I keep bothering you guys? ;)
 
It's nice that you have this course option (in some scenarios, students are simply let off the hook). Higher education ought to always strain student's brains witha little number work. A well-rounded education must include some increase in numerical literacy, so I'm glad that you're working with numbers, whatever the form.

As long as you continue to include your thoughts or efforts, you are free to start as many threads as needed.
 
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I will!

mmm4444bot said:
It's nice that you have this course option (in some scenarios, students are simply let off the hook). Higher education ought to always strain student's brains witha little number work. A well-rounded education must include some increase in numerical literacy, so I'm glad that you're working with numbers, whatever the form.

As long as you continue to include your thoughts or efforts, you are free to start as many threads as needed.
Click to expand...

I will, thank you!
 
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