From 9:00 am to 12:00 noon, what is the angle formed by the clock face that the hour hand traverses?
从上午9时到中午12时，时针所走过的钟面形成的夹角是多少°
<gadget id="calculator">12 - 9</gadget>
<output>3</output>

<gadget id="calculator">30 * 3</gadget>
<output>90</output>

<result>90</result>