Most schools have their courses listed on their website. Middle Schools/Junior High, High School, Colleges. And the course titles vary. I've never seen Two though. I would do it to match how schools do it.
My 8th grade daughter is currently taking "Math 1." This is actually 9th grade math. In our current school district, they got rid of Algebra and Geometry as courses and combine them all into Math 1 and Math 2 and Math 3 (for 9th-11th grades) then move on to AP Calculus A/B and AP Calculus B/C.
In the district where my daughter might go to high school next year, they have the older version where each year is a type of math. Algebra 1, Algebra 2, Geometry, Statistics, Pre-Calculus, AP Calculus (only one level at that school).
For AP classes, check online for the AP test names. They're all listed in multiple places. Nearly all high schools will name their AP classes by the names of the AP tests.
If your characters are in college, just check out some college course catalogs.
So the short answer is, duplicate what the schools call the courses. Don't try to come up with a new style or base it on how one might do other numbers.