Author note — to cover

Cover compound interest year by year: interest earned on the growing balance, tabulating balances over two or three years, and the contrast with simple interest's flat additions. Small n by repeated multiplication only; the one-step power formula is the sibling page. Simple interest itself lives under Percentage change. Both tiers, since R16 does not brace compound interest. (R16, R9)

Introduction

—coming soon—

Practice and continue

Practice

Compound interest

Interest paid on the balance, so each year's interest earns interest itself.

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The compound interest formula

Raising the multiplier to the number of years to reach the balance in one step.