Mind-Bending Math & GamesExponential Growth
The Rule of 72
Divide 72 by an interest rate to find how long money takes to double
Your savings earn a little interest each year. Could you work out in your head when they'll double?
You'll find out
- The one number that does the math
- How close a mental shortcut gets
- What it says about prices and debts
Why it matters
Savings, prices, debts and towns all grow by a percentage, and one division tells you when they double.
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