We can "rename" a sentense with python variables, like alias in Terminal. e.g. is_admin = Txn.sender() == App.globalGet(Bytes("admin"))
Add, Mul, Div, Sub, Mod, Exp, and other math functions are supported by PyTeal. We can use just +, -, *, /, %, **, with Int() class to do it (prefer this way).
Sracthing App.globalGet is not needed. In the example they were just to show the capability of PyTeal.
Problem: "pseudo random generator" code is very clearly shown on the blockchain ajnd easy to solve. If we want to cheat, a little reverse-engineer work with frontend manipulation is all we need.