Chapter 2
The Mathematics of Money

Every chapter after this one leans on the same small toolbox. One force — inflation, which compounds against you. One engine — compound growth, which compounds for you. And a handful of operations built on the pair: deflating dollars across time, discounting future cash back to the present, pricing streams of payments, and deciding what a return must clear before it counts as a return at all. None of it is harder than high-school algebra, and all of it is load-bearing: the retirement number, the mortgage decision, and the valuation of every asset in this book reduce to these few moves. Learn them once, here, and every later chapter gets shorter.