Difference between permutations of any given two n digit numbers is always an integer multiple of nine?
Show that $n-m$ is a multiple of 9 when $n$ and $m$ have same digits
I have these two CREATE TABLE statements:   CREATE TABLE GUEST (   id int(15) not null auto_increment PRIMARY KEY,   GuestName char(25) not null );  CREATE TABLE PAYMENT (   id int(15) not null auto_increment   Foreign Key(id) references GUEST(id),   BillNr int(15) not null );   What is the problem in the second statement? It did not create a new table. Deleting comment removes "Add comment" link on Mobile If I delete a comment on the mobile version of the site (at least if it's the only comment on an answer), the "Add comment" link will vanish along with the comment, so I have to reload to leave another comment.     but got declined as , which is why I'm reposting this (as it may well be a new bug with the same symptoms).  I'm using Firefox 32.0.3 on Android. I (think) that I've configured a static IP address in /etc/network/interfaces:  # The primary network interface  auto eth0  iface eth0 inet static     address 10.1.1.2     netmask 255.255.255.0     network 10.1.1.0     broadcast 10.1.1.255     gateway 10.1.1.1   And I change the file /etc/resolv.conf to include the desired nameservers.   Then I restart networking sudo /etc/init.d/networking restart  But after some hours resolv.conf always reverts back to the DHCP nameserver.   I should also say that this is Ubuntu Server with only l0 and eth0 interfaces. Do we really need a [source-code] tag? The  tag doesn't appear to be very useful.  It's used in a variety of ways (for reading, writing, showing, transforming, compiling, translating, obfuscating, obtaining, ... source code) on 1747 questions right now, and doesn't appear to be adding any classification value to the site.  Can we get rid of it? How to find a starting point for root finding in complex plane? The function $f(x) = x^2 +1$ has zeros in the complex plane at $x = +i$ and $x = -i$. Is there a real starting point for complex Newton's method such that the iterates converge to either of these zeros? Is there a complex starting point too?  I know that Newton's method for finding roots is $x_{n+1} = x_n - \frac {f(x)}{f'(x)}$. But I don't know how to find the proper starting point. Get month name from Date Is it true that all numbers of the form $\sqrt[b_1]{a_1}+\sqrt[b_2]{a_2}+\cdots+\sqrt[b_k]{a_k}$ are not integers, where $a_i,b_i$ are positive integers such that none of the $k$ terms is an integer? I think this must be a theorem somewhere, probably a fundamental theorem in number theory, but not sure what it would be called. Types of books or Types of book? can anybody tell me which one of these is the correct one? I have been searching all over the internet but I have still got no answer.  Types of books Types of book Expanding the equation out gives  $(3^{2n}\times3)+(2^n\times2^2) \equiv 0\pmod{7}$   Is this correct? I'm a little hazy on my index laws.  Not sure if this is what I need to do? Am I on the right track? What is rank deficiency, and how to deal with it? Webforms and jQuery, how to match the ID's? I want to use jQuery with asp.net webfoms.  Do I need to get a special toolkit so the .net controls spit out friendly Control ID's?  Reason being, I don't want to write javascript referencing my html ID's like control_123_asdfcontrol_234.  Has this been addressed in version 3.5?  (I remember reading you have to get some special dll that makes ID's friendly). Single quotes vs. double quotes in Python According to the documentation, they're pretty much interchangeable.  Is there a stylistic reason to use one over the other? What is a rocket engine thrusting against in space? I know Newton's third law of motion might be the answer for this but still I am wondering how the rockets could thrust in the empty space and move in the opposite direction. I guess an astronaut wouldn't be able to push in the empty space with his hands or legs to move himself, but with a rocket engine it's possible. How? What might be the explanation for this in General Relativity? Last activity on question shows modified by user who did not ask or answer .       The  has no sign of the user sharth The  also does not have any sign of related activity   I would like to know why the user's name is associated with the question. At least why their display name shows up as having modified the question timeline activity.  Possible reason that I can think of is that, .  Is this the reason?  Is there a way (for normal users), to look for such details, other than looking at the user activity and the question's revision history. The volume "filesystem root" has only 0 bytes disk space remaining? Functions of Independent Random Variables Is the claim that functions of independent random variables are themselves independent, true?   I have seen that result often used implicitly in some proofs, for example in the proof of independence between the sample mean and the sample variance of a normal distribution, but I have not been able to find justification for it. It seems that some authors take it as given but I am not certain that this is always the case. Where can I find stock or custom ROMs for my Android device? What are attributes in .NET? we have been using the Find Nearby Accounts app from appexchange for a while now. The app uses the Google Maps API vs 2 which is now deprecated and hence has rendered the app ineffective. I have tried migrating the Google maps API version for the app from v2 to v3 by generating a v3 API key. The URL for my salesforce instance was included in the creation of the Client ID under API Access. After all these steps, I still get the error "Problem with Address. I know the address is right.   Has anyone been able to get this working? Thanks. Can I run Android apps on Ubuntu?