pan class="hljs-number">10.5555</span>)         <span class="hljs-comment">// 1.06e1</span>
f3(<span class="hljs-number">100.5555</span>)        <span class="hljs-comment">// 1.01e2</span>
f3(<span class="hljs-number">1000.5555</span>)       <span class="hljs-comment">// 1e3</span>
f3(<span class="hljs-number">1000000.5555</span>)    <span class="hljs-comment">// 1e6</span>
f3(<span class="hljs-number">1200000.5555</span>)    <span class="hljs-comment">// 1.2e6</span>

<span class="hljs-comment">// create a