Odd numbers starting from 1: 1, 3, 5, 7, ... What is the 100th odd number.
从1开始的奇数：1，3，5，7，…其中第100个奇数是多少．
<gadget id="calculator">100 * 2</gadget>
<output>200</output>

<gadget id="calculator">200 - 1</gadget>
<output>199</output>

<result>199</result>