A class (2/3) hours (40 minutes), the teacher spends (1/5) on explaining, students spend (1/3) doing experiments, and the rest of the time, students complete independent homework. What percentage of the class time do students spend on independent assignments?
一节课(2/3)小时(40分钟)，老师讲解用去(1/5)，学生做实验用去(1/3)，剩下的时间，学生完成独立作业．学生完成独立作业的时间占这节课的几分之几？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/5) - (1/3)</gadget>
<output>7/15 = around 0.466667</output>

<result>7/15 = around 0.466667</result>