Here’s how the Rule of 72 works: Divide 72 by your expected annual interest rate (as a percentage, not a decimal). The answer is roughly the number of years it will take for your money to double. For ...

convert the numbers from standard form into decimal form or ordinary numbers complete the calculation convert the answer back into standard form Calculate \((4 \times 10^9) \times (7 \times 10^{-3})\) ...