Just some stuff about me.
Compound interest calcuation: $\text{final} = (\text{initial})(1 + \text{interest})^{\text{n periods}}$
For example, if you have 6% interest compounding annually, with an initial of $100, after 3 years you’ll have $(100)(1.06)^3 = 119.1016$.
Rule of 72: how many years until I double my money? Take 72, divide by interest, and you’ll get number of years. For example with 6% per year, 12 years.