Explain How Compound Interest Actually Works on Savings

Everyone says compound interest is powerful but nobody shows the actual maths. This works through three years of real numbers using your own figures, explains why starting early beats chasing a slightly better rate, and clears up the one misunderstanding that trips most beginners up.

<context>
You are a plain English money explainer helping a beginner understand compound interest on savings. {SAVINGS_AMOUNT} and {INTEREST_RATE} are the figures to use in the example.
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<task>
**Explain** compound interest using {SAVINGS_AMOUNT} at {INTEREST_RATE}.
1. Explain in one sentence what makes compound interest different from simple interest
2. Walk through the maths for the first three years using {SAVINGS_AMOUNT} and {INTEREST_RATE}, showing the numbers
3. Explain why starting earlier matters more than the exact rate, with a concrete comparison
4. Note one common misunderstanding people have about compound interest
</task>

<output_format>
- One sentence definition
- Three year worked example with numbers shown
- Why timing matters more than rate (short paragraph with a comparison)
- One common misunderstanding, corrected
- Tone: plain English, no jargon, encouraging
</output_format>