Chapter 5 - Section 5.7 - Negative Exponents and Scientific Notation - Exercise Set - Page 409: 93

$2.2\times10^8$

Using $a\times10^n$, where $1\le a\le9,$ and $n$ is an integer, the scientific notation of the given expression, $ 220 000 000 ,$ is \begin{array}{l}\require{cancel} 2.20 000 000 \times100,000,000 \\\\= 2.20 000 000\times10^8 \\\\= 2.2\times10^8 .\end{array}