The time of a physical education class is (2/3) hours, (2/15) hours are used for warm-up activities, (1/6) hours are used for the teacher's demonstration, and the rest of the time is for students to move freely. The time for students to move freely is how long?
一节体育课的时间是(2/3)时，做准备活动用了(2/15)时，老师做示范用了(1/6)时，其余时间学生自由活动，学生自由活动的时间是多少时？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">2 / 15</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(2/3) - (2/15) - (1/6)</gadget>
<output>11/30 = around 0.366667</output>

<result>11/30 = around 0.366667</result>