Counting possible outcomes that the order does not matter.
To find the full list of all Precalculus and Geometry lessons, go to,
Precalculus-
https://docs.google.com/spreadsheets/d/1ZFS-4w3DNUCrb7W-jQKCC8PnlUBvWRkd3KBW2xyE2RA/edit#gid=0
Geometry-
https://docs.google.com/spreadsheets/d/1TErwbbN6CndcQPymLxr_dz4Ficq1BYaN4bvHoGU4amI/edit#gid=0
