Addition, comparison and calculator notation

For addition or subtraction, first write the numbers using the same power of ten. Then combine the coefficients. For positive standard-form numbers, compare exponents first; if equal, compare coefficients.

Example

\(\begin{aligned}4.2\times10^6+7.5\times10^5&=(4.2+0.75)\times10^6\\&=4.95\times10^6\end{aligned}\)

\(9.8\times10^4<1.2\times10^5\), even though \(9.8>1.2\), because \(98000<120000\).

A calculator display such as \(3.7\mathrm{E}{-6}\) means \(3.7\times10^{-6}\). Use the calculator’s scientific-notation entry key as its manual directs and bracket entire terms when dividing. Do not add exponents when adding numbers.