40 points per class, 6 classes per day, how many hours per day.
一节课40分，每天上6节课，每天上多少小时课．
<gadget id="calculator">6 / 60</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">40 * (1/10)</gadget>
<output>4</output>

<result>4</result>