Enrollment Policies
Important Information For All Students
 This page discusses the process of enrolling in the following courses: Math 105L, 106L, 111L, 112L, 122L, 202, 212, 216, 353.
 Enrollment in full section of these highdemand courses in the Mathematics Department is mostly handled by the wait lists.
 While wait lists are in operation, you should not need a permission number to enroll in any open section (a section with available seats) of any of these courses that would be appropriate for you to take. The Mathematics Department does not use permission numbers to control enrollment in these courses.
 The Mathematics Department does not give permission numbers for these courses while the wait lists are in operation, other than in exceptional circumstances (such as a secondsemester senior who needs the course to graduate), or unusual cases of students being eligible to take a course without having satisfied an enforced prerequisite (such as Trinity students not majoring in math who are interested in taking Math 216).
 Please do not contact instructors of these courses in the Mathematics Department to request permission numbers for their section of a course while wait lists are in operation.
 The Associate Chair and the Supervisor of FirstYear Instruction will be keeping a close eye on enrollments until the end of drop/add, and will make every effort to accommodate as many students as possible.
Be sure to click through all of the tabs below that might be relevant to your issue.
 High Demand Courses & Wait Lists
 Misunderstandings about Wait Lists
 Wait List Scenarios & Strategies
 Prerequisites & Permission Numbers
 After Wait Lists are Erased
 Changing Classes
High Demand Courses & Wait Lists
If your preferred section is full, please enroll in any section that is open that fits with your desired schedule. If that is not possible, you may need to consider adjusting your other classes to get into an open section.
If your conflict with open sections involves classes that you must take that semester for your major, then add yourself to the wait list for any other section (ideally the wait list with the fewest students on it). This will maximize your chances to get in as other students shuffle their schedules, or if (in some cases) enrollment caps might rise.
Make sure you have a backup plan because putting your name on the wait list does not guarantee you will get any section of the course. Depending on the needs of your schedule, your backup plan might be to take another section of the same course or a course in a different department. In either case, it should definitely be a class where the enrollment is such that you are certain to get an available seat.
Because you cannot assume that you will/will not get in to the section you are on a wait list for, you should attend BOTH the wait listed section and the backup class.
Students in the Pratt School of Engineering should make sure to communicate any scheduling problems to their academic dean.
After the wait lists have been erased, if you were unable to enroll in any section of the appropriate course without sacrificing courses critical to your major, please contact the Supervisor of FirstYear Instruction (SFI) at sfi@math.duke.edu. (See also "After Wait Lists Are Erased".)
Incoming students, you will not be allowed to join wait lists before you arrive at Duke in the fall of your freshman year; this is a University policy, not a Mathematics Department policy. You will be allowed to join wait lists in the week before classes begin after you have met with your premajor advisor. NOTE: If you want to get onto a particular wait list as soon as possible, you can ask your advisor for their earliest possible meeting time, usually on Wednesday of that week. After your advisor talks to you about your courses and makes you eligible to enroll, you can then add yourself to a wait list.
If you are planning to join a wait list in August, then for now you might consider filling the fourth spot in your schedule with a course that you might realistically want to take  perhaps an alternative elective, for example. This additional flexibility (you could drop the alternative elective OR the original elective) will make it easier for you in August when you are trying to get onto the best possible wait list at that time.
Misunderstandings about Wait Lists
Wait lists are set up to help make the registration process more orderly. Students often misunderstand this, perhaps on some level overinterpreting the wait list as a complete and fully automated tool for registering for the most desirable section. Critically, this is not the case. (For official discussion of how the wait lists work, please refer to the Office of the Registrar.)
Most importantly, students should understand that being on a wait list does not mean that you will be enrolled in that section. If there is insufficient movement from the roster, you will not be enrolled. A student who is not enrolled into a section from the wait list is not entitled to special consideration afterwards.
Students are also often very surprised to learn, sometimes unfortunately through personal experience, that when a seat opens up in a section, the first person on the wait list is NOT always the one who gets that seat. The system will try to enroll the first person on the list, but if that attempt is unsuccessful, for any reason, it will skip the first person and go on to the next person on the list. (It is not rare for a student in position #4 on the wait list to get the newly open seat, after the system failed to enroll the students in positions #13!)
There are several things that might prevent the system from enrolling a student in the course, including (but not necessarily limited to):
 The student might already be enrolled in another section of the same course.
 The student might be enrolled in another course with a time conflict with the wait listed section.
 The student might not yet have received permission to take that many credits.
The ACES system gives no indication to a student on a wait list that such an enrollment problem will prevent enrollment. It is entirely the responsibility of the student to avoid these sorts of problems. A student who is skipped over on a wait list for a reason such as these is not entitled to special consideration afterwards.
Because of the risk discussed above, it is not recommended that you sign up for a wait list for one section of a course if you are keeping your enrolled seat in another section of the same course, or a timeconflicting course.
If you do this anyway, be sure to understand that you will not be enrolled from the wait list as long as this circumstance remains. So it is essential to keep a very close eye on your position in the wait list. If you are in position #1, clearly there is no point in having that position if you cannot be enrolled from it. If you are in position #2, 3, or 4, note that you could still be preventing yourself from being enrolled  because, as noted above, the students ahead of you on the wait list might also be enrolled in other sections, and the system might be passing you up after trying to enroll you, after having passed up the other students!
Consider these dangers very carefully before you sign up for a wait list for one section while keeping your enrolled seat in another section.
Wait List Scenarios & Strategies
Students should be sure to understand that we cannot guarantee seats for all interested students when courses are in high demand. Along those lines, note that if you play one of the "risky" strategies below, the risk is entirely yours.
Below are some potential scenarios and some strategies to consider.
If one section of a course is more desirable to you than the one that you are enrolled in: 

Recommended: Stay in the section you are currently enrolled in, and keep a regular eye on the wait list for the other section. Sometimes, especially after classes begin, students shuffle their schedules around significantly, and there might be significant movement on that wait list. If open seats become available, you can then add that section.  Risky (not recommended): You could drop your current section and add yourself to the wait list of the desired section, hoping that with movement on this waitlist you will be in line ahead of students following the recommended strategy above.
While this does increase your chances of getting into the desired section, note that it also increases your chances of not getting into the course at all. Wait lists do not always move significantly, and are impossible to predict. Note also that other students on this and other wait lists for the course in question could easily decide to play it safe, and enroll in your previous section. All of the sections could fill up in this way, leaving you unable to take the course this term. So, if you do take this risky strategy, you should make sure to keep an eye on the enrollment and wait lists for all of the sections of the course, and be prepared to move back into an open section. 
If all of the sections that fit with your desired schedule are full: 

Recommended: Realize that you might simply not be able to get the desired schedule that you were hoping for. Some of the other classes on your desired schedule might be electives, and you could consider taking a different elective to get into an open section of the needed math course. Some of the other classes on your desired schedule might be required for your major, but could be taken in a different term, and you could consider taking a different course that would be equivalently effective for your major. Or, it could be that the math course you are trying to get into might be the one that is of the lowest priority. If you don't need to take math for your major, or if it can be postponed without serious consequence, you might consider arranging a new schedule for the semester that does not include math. You can still add yourself to a wait list, and hope that you might get in, but you will have a fallback plan in case you do not. Note, if you are taking math classes because they are required for your major, it is very possible that those math classes are prerequisites for particular courses in your major. If this is the case, postponing your math classes will delay your preparations for those courses. For this reason, it is very often more desirable to prioritize your math classes, and choose other courses on your desired schedule to delay. 
Risky (not recommended): You could join a waitlist for a math section that fits your desired schedule, in the hopes that it will all work out. Of course there is no guarantee that it will, and you might end up unable to take the course. If the other courses on your desired schedule are sufficiently important that it is worth that risk, then this might be the right gamble. If you do take this gamble, be sure to have a backup plan in case you do not get into the math course for which you were waiting. Remember though that math classes very often are prerequisites for other courses that might be important for your major. So, for many students, this will be a gamble with a significant potential down side. 
You are on a wait list, not sure if you should attend that section, since you are not yet enrolled. 

Recommended: Attend the lectures for that section as if you were enrolled! It is also recommended that you let the instructor know that you are attending the classes and keeping up with the work for the course. Instructors will expect you to do this, so that if you do get in to the class, you will already be up to speed and will not need to do any make up work. Of course you should also have a backup plan in case you do not get in to the math class in question  you should be attending that class also, for the same reasons. If you do not get in to the class, then your only loss is that you attended a few extra lectures. Of course if you take that class in a future term, what you learned in those few lectures could still end up being valuable knowledge. 
Risky (not recommended): You might consider not attending the lectures, and then if you do not get in to the class you will not have spent time on something that did not have direct bearing on your schedule of classes for this semester. But, if you do get in to the class, you will be significantly behind on learning the material for the course. The instructors cannot be expected to give you individual lessons on that missed material, and so you will have to learn it on your own, which of course is a significant disadvantage. You might also be behind on the assignments for the course. While the instructor might allow you to turn in those assignments a little bit late, you will need to complete those assignments while also teaching yourself the material already covered, trying to follow the new material, and also doing the current class assignments (all of this in addition to all of your other classes as well). At best, this significant extra load to an already full schedule will be an extremely difficult challenge until you catch up, and will hurt your understanding of the material in the course; at worst, you might find that you can never really fully catch up, in which case it would be expected that you would perform poorly on the exams and in the course.

Prerequisites & Permission Numbers
While the wait lists are in operation, you should not need a permission number to enroll in any open section of any of these courses that would be appropriate for you to take. Note, the way ACES is set up, it might appear that a permission number is needed as you are signing up for a course, due to the appearance of a box labeled "Permission Number"; this is there to be used only if a permission number is actually required, and thus is misleading for courses in which a permission number is not required. The Mathematics Department does not use permission numbers to control enrollment in these courses.
In fact, you would also not need a permission number even to enroll in many courses that would be too advanced for you to take  so make sure that you have carefully read the Placement Guidelines information and Placement FAQ's, and that you have noted all of the prerequisites listed in the Bulletin for the course that you are interested in.
Very few of the prerequisites for courses in the Mathematics Department are enforced by ACES. Most of our enforced requirements are there simply to make sure that you are selecting the right course for you at a particular level, or to keep you from taking a course that would repeat material from a course for which you already have credit at Duke  not to keep you from enrolling in a course at too high of a level.
Enforced prerequisites are satisfied only by course credits on your Duke record. It is the responsibility of the student to ensure that credits for enforced prerequisite courses appear on your Duke record, in a timely manner, to allow you to enroll; anticipated/pending transfer credits, anticipated summer credits, pending AP credits, pending prematriculation credits, and unreported AP scores will not be viewed as equivalent and do not make you eligible for a permission number. (See the Registrar's webpage for information on how to have your AP or international placement scores officially reported to Duke.)
Here are discussions of the enforced requirements of some particular courses in the Mathematics Department:
 Math 105L Laboratory Calculus and Functions I has no prerequisites. Anyone can enroll in this course who does not already have credit for 111L Laboratory Calculus I.
 Math 106L Laboratory Calculus and Functions II requires credit for Math 105L Laboratory Calculus and Functions I, as this is a twocourse sequence.
 Math 111L Laboratory Calculus I has no prerequisites. Anyone can enroll in this course who does not already have credit for 105L or 106L.
 Math 112L Laboratory Calculus II requires credit for Math 106L or Math 111L at Duke, as it is part of those two sequences. (This requirement is relaxed in Spring terms, as the alternative course Math 122L is not offered.)
 Math 122L Introductory Calculus II does not allow students who have credit for 106L or 111L. Students with credit for either of those courses are in the L sequence of calculus courses and must stay in that sequence, in which the next course is Math 112L.
 Math 112L and Math 122L cover roughly the same material. Students cannot receive credit for both of these courses.
 Math 202 and Math 212 require credit for second semester calculus (Math 22, 112L, 122L, or 122). AP/IPC credits must be on your Duke record as Math 22; the Mathematics Department cannot accept alternative evidence of scores expected to result in this credit. See these course webpages for information about the Math 122L Proficiency Exam if you are confident in your proficiency with second semester calculus despite not having such credit.
 Math 202 Multivariable Calculus for Economics, Math 212 Muiltivariable Calculus, and Math 222 Advanced Multivariable Calculus cover similar material. Students cannot receive credit for more than one of these courses.
 Math 221 Linear Algebra and Applications and Math 216 Linear Algebra and Differential Equations cover similar material. Students cannot receive credit for both of these courses.
 Math 216 requires credit for Math 202, 212, or 222, and is not open to students who have credit for Math 221 or Math 356 Elementary Differential Equations.
 Math 353 Ordinary and Partial Differential Equations requires credit for Math 216, and is not open to students who have credit for Math 356.
If you are planning to take a course for which you do not have a prerequisite that is not enforced (perhaps you want to take Math 122L but you do not have credit for Math 21 (AP credit)), be sure to note that your ability to enroll in the class does not necessarily mean that it is a good idea. For example, it could be that one of the requirements for your intended major is that you have credit for the class you are skipping. Critically, students should realize that concerns about skipping math courses required for a major or minor should be addressed to the department in question, not the Mathematics Department.
Note, unlike Duke credits, AP credits can be forfeited. So, for example, if you have AP credit for Math 22 you can still enroll in Math 122L. But if you have credit for Math 112L taken at Duke, or transfer credit for Math 122 taken at another university, you cannot enroll in Math 122L. If you have AP credits, you are encouraged to keep them and enroll in the next course in the sequence appropriate to your situation, but you are free to consider forfeiting them and enrolling in a lower level course.
If you are not certain what would be the right course for you to take, you should be able to determine the right answer by reading the Placement Page and the Placement FAQ Page.
After Wait Lists are Erased
Most students should have their schedules finalized before the wait lists are erased. For the remainder of the drop/add period, adding any class requires a permission number.
Note that adding a class at this time is often difficult, as that class will have covered already a substantial amount of material, and written assignments will have been collected. If you are allowed to add that class, you will have to make up all of that missed work, probably on your own  while also doing the continuing work for the course, and keeping up with all of your other classes. Students should consider carefully the question of whether accomplishing this is realistic, and be aware that being unsuccessful in such an attempt would probably result in a poor performance in that class.
Instructors are also keenly aware of this issue; accordingly, instructors are within their rights not to accept further students into their classes. The Mathematics Department might also conclude that adding a course at such a time would not be appropriate, and not allow a student into a course. Adding a lab calculus course after the wait lists are erased is particularly problematic in this way due to the lab schedule and class content.
Another difficulty is that, of course, the class you are interested in might be full. Be aware that the Mathematics Department usually does not allow students into sections that are full.
If you are interested in adding a class during the drop/add period after the wait lists have been erased:
 If you are already enrolled in a different section of that course, if you have been doing the work for the course, and if there are seats available in the section you want to switch to, contact the instructor of the desired section to request a permission number.
 If you have been attending a higher level course and want to "drop down" to a lower level course (for example, from Math 122L to Math 111L), and if there are seats available in the section you want to take, you should discuss your case with the Supervisor of FirstYear Instruction. Be aware that, depending on details, it may be too late to add the course. (See discussion below on Changing Classes.)
 If you want to move up to a higher level course, you should discuss your case with the Supervisor of FirstYear Instruction. You will need to establish that you are qualified for the higher level course; see the Placement Page for details. You will also need to establish that you will be able to catch up on missed material and work in a timely manner. Be aware that, depending on details, it may be too late to add the course. (See discussion below on Changing Classes.)
 If all open sections of the desired course conflict with required classes in your schedule, you should discuss your case with the Supervisor of FirstYear Instruction.
When you contact either the instructor or the Supervisor of FirstYear Instruction (as directed above), please be sure to include all of the information necessary to establish that you are qualified for the course, as described above. (See the Placement Page for discussion on placement qualifications.)
Recall that time is a very important factor in deciding if it is advisable for you to add a class, so you are urged to follow the instructions above as soon as you can. For example, a request to add a class late in the second week of classes is unlikely to be granted.
Once you have received a permission number, please add the course PROMPTLY. Be aware that until you actually enroll, there is the possibility that the section might fill up and you might be denied entrance into that new section. It is not appropriate to request a permission number that you do not intend to use promptly.
Changing Classes
Most students should be able to determine their proper placement from the Placement Page; and students with borderline or otherwise complicated cases can get advice from the SFI Placement Advice page. The SFI is also usually available for consultations before the start of the term. All of these resources can and should be accessed before classes begin; so, most students should start the term in the correct class.
The first week of classes is then an opportunity for students to confirm their placement. Students who might want to change to a different class can do so for the entire first week. Note, this is a significant amount of registration flexibility afforded to students, because in this first week classes are covering material, doing group work, and completing graded items both in class and out of class. Because of this significant and important activity, it is important for students to try to get into the proper class as early as possible in that first week; joining a math class late in the first week will require a significant effort, even for students with a previous exposure to similar high school or college courses.
It is the responsibility of the student to ensure by the end of the first week that he or she has the necessary background, qualifications, and resources that will be needed to do well in the math class in which he or she is enrolled.
By the beginning of the second week, courses in the Mathematics Department have moved forward to an extent that joining the course in a way that is feasible, fair to the other students, and consistent with the philosophy of the course might not be possible. Either the course instructor or the Mathematics Department might disallow such a request.
Dropping Back to a Lower Course
Some departments allow students to "drop back" to a lower level course with a later deadline than that for students who have not been attending a course in that department. Such a policy, when feasible, can be encouraging and convenient for students who are not entirely confident in their placement choice.
However, due to the tailored content and assigned work of each individual course, such an option is not realistic for lab calculus courses in the Mathematics Department. Specifically, having attended a higher level course and attempting to "drop back" to a lower course (or, similarly, "jumping up" to a higher level course) is usually not much easier (or more likely to be allowed) than simply adding that course late in the drop/add period.
The lab work in these courses is central to the course structure and philosophy, and is not part of the calculus curriculum of most high schools or other universities. Students who have missed even one lab meeting will have significant difficulty in catching up in the material and work of the course fully and fairly. Students who have missed more than one lab meeting are unlikely to be allowed into the course.
Strategies to Succeed
If you are less than confident that you have the appropriate preparation for and resources to dedicate to taking the math course you have selected, you should consider attending and participating in BOTH that course and the lower level course that you might need to consider dropping down to. Note, you can attend such a course and participate in the work even without being registered (though of course you will need to have the lab manual in order to participate!). This participation will significantly extend the point in the term by which you will be able and allowed to change your mind to take the lower level course. And, of course, if you decide that your initial higher placement is satisfactory, then your continued participation in the lower level course is not necessary.