A machine only gives back 80% of what it has taken over its life time. Does not mean you get back 80%.
You lose 99% of chances you dont take, but with gambling you lose 99% of what you DO take.
There is no math, secrets, or patterns behind the software, unless its a computing pattern, but the way these machines are built nowadays its impossible to even find that pattern.
And yes its rigged, everyone knows you're not gonna make money by gambling.. youve probably spent so much as the casino that any wins at this point is only making back a small portion of the majority youve lost.