Xiao Ming counted the time allocation of a math class: (1/5) hour was used for the practical operation, (1/6) hour was used for the teacher's explanation, and the rest was practice time. It is known that each class is (2/3) hours, how many hours did the students practice?
小明统计了一节数学课的时间分配：实践操作用了(1/5)小时，教师讲解用(1/6)小时，其余的都是练习时间．已知每节课是(2/3)小时，学生练习用了多少小时？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">(2/3) - (1/5) - (1/6)</gadget>
<output>3/10 = around 0.3</output>

<result>3/10 = around 0.3</result>