On the clock face, the hour hand rotates 90 degrees clockwise from "2".
钟面上，时针从"2"沿顺时针方向旋转90度到多少．
<gadget id="calculator">90 / 30</gadget>
<output>3</output>

<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<result>5</result>