There are 22 cars and motorcycles in the parking lot, and there are 58 wheels. How many motorcycles are there?
停车场有小轿车和摩托车共22辆车，车轮有58个，问摩托车多少辆．
<gadget id="calculator">22 * 4</gadget>
<output>88</output>

<gadget id="calculator">88 - 58</gadget>
<output>30</output>

<gadget id="calculator">4 - 2</gadget>
<output>2</output>

<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<result>15</result>