Same deposit, same rate, two paths. Simple interest adds the same flat rent every year — a straight line. Compound interest re-invests each year's rent — a curve that bends upward. In year one they tie exactly. After that, compound pulls ahead: slowly at first, then unstoppably. Over a few years the gap is pocket change; over a few decades it is the whole fortune.

This lesson asks you to see BOTH paths on one deposit: estimate who wins, compute the simple balance, then put an exact number on compound's edge. Watch that gap as the years stack — it more than doubles every year it is given. That accelerating gap is the entire reason the word compound exists.