If you save $$300$ per month for the next $45$ years with an annual investment return of $10\%,$ your savings could grow to over $$3$ million. But how much of this amount comes from "interest on interest" and "interest on the principal"?

$$3\mathrm{.}14$ million minus $$162000$

$$162000$

slightly over $$1$ million

approximately $$2$ million