**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 two-course 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.