A positive number in scientific notation is written as \(a\times10^k\), where \(1\le a<10\) and \(k\in\mathbb Z\). The exponent records the place value; normalise the coefficient after calculating.
| Operation | Method | Example |
|---|---|---|
| Multiply | Multiply coefficients; add exponents. | \((3\times10^5)(4\times10^{-2})=1.2\times10^4\) |
| Divide | Divide coefficients; subtract exponents. | \(\dfrac{6\times10^{-4}}{2\times10^3}=3\times10^{-7}\) |
| Add or subtract | Express both quantities with the same power of ten. | \(4.2\times10^6+3\times10^5=4.5\times10^6\) |
Example
\(0.000072=7.2\times10^{-5}\). The negative exponent makes the number small; it does not make the number negative.
Rewrite a calculator display such as 7.2E−5 as \(7.2\times10^{-5}\). Keep full calculator precision during a calculation and round only the final answer as requested. Calculator E notation is not acceptable as a final answer.
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