Purchasing Power Parity (PPP)
The idea that exchange rates should drift toward levels where a basket of goods costs the same everywhere — the theory behind the Big Mac index. It anchors long-run currency values, if not day-to-day ones.
Where this is taught
Definitions are the trailer. These free levels turn Purchasing Power Parity into something you play — one bite-size lesson, with worked examples, a quiz and XP.