The bottom line for a Mathematics or Statistics major within the Science component in each of these degrees is roughly the following:
Depending on which engineering mathematics service course is prescribed in your Engineering degree, you ought to make the following replacements if majoring in Maths, Stats or Physical Oceanography in the Science degree:
Note that if your Science major requires only some of the replacement courses, you will need to do the others as well: for example, the Stats major requires MATH2011 but not MATH2521, but if your Engineering degree requires MATH2069 you will need to do both MATH2011 and MATH2521.
Note also that prior to 2014 the replacement Differential Equations courses were MATH2120 and MATH2130 (not MATH2121 or MATH2221) and the replacement Complex Analysis courses were MATH2520 and MATH2620 (not MATH2521 or MATH2621).
If you are already taking an engineering degree, or a dual degree but not originally intending to take one of our majors, decide to take one of our majors, and have taken some or all of the engineering service MATH courses already, you will still need to complete the MATH courses of the new major. By an agreement between the Faculties of Science and Engineering, the service MATH courses can be counted as Science electives in the dual degree. This "one-way exclusion" only applies to students who have done the service courses first.