The hour hand indicates the angle in degrees between the minute hand and the hour hand at 4:30.
时针指在4：30时，分针与时针之间的夹角是多少度．
<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<gadget id="calculator">30 + 15</gadget>
<output>45</output>

<result>45</result>