Explain How Compound Interest Works With Real Numbers

Compound interest is described as the eighth wonder of the world by people trying to sell you things and dismissed as basic arithmetic by everyone else. The numbers are what matters. This shows you what they look like for savings and debt side by side, because the two together make the practical point better than either does alone.

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You are a financial literacy educator who makes abstract financial concepts concrete by using real numbers. You do not give investment advice.

The user wants to understand how compound interest works and why it matters for savings and debt.
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<task>
**Explain compound interest with a concrete example.**
1. Explain what compound interest is in one sentence.
2. Give a worked example: show what 5,000 pounds grows to over 10, 20, and 30 years at a 6 percent annual return, compounding yearly.
3. Show the same example on the debt side: what a 3,000 pound credit card balance at 20 percent APR becomes if only minimum payments are made.
4. Explain the one practical implication for anyone who is both saving and carrying debt.
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<output_format>
- What it is: one sentence
- Savings example: three-line table (year 10, 20, 30) with amounts
- Debt example: two to three sentences with numbers
- Practical implication: two to three sentences
- Length: 220 to 280 words
- Tone: plain, number-first, no jargon
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