How many minutes did the minute hand move from the number 3 to the number 7 on the clock face?
分针在钟面上从数字3走到数字7，一共走了多少分钟．
<gadget id="calculator">7 - 3</gadget>
<output>4</output>

<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<result>20</result>