An experimental class (2/3) hours, of which (1/5) is used for the teacher's guidance and explanation, (3/10) for the students to operate the experiment, and the rest of the time is for the students to write the experiment report, and the experiment report uses the whole How much is the class?
一节实验课(2/3)小时，其中老师指导讲解用了(1/5)，同学们操作实验用了(3/10)，其余的时间是同学们写实验报告，实验报告用了全课的几分之几？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (1/5) - (3/10)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>