Xiaohong conducted a survey on the travel situation of the students in this class. (1/3) students go to school by car, (2/5) students go to school by their parent's bicycle or motorcycle, and the rest go to school on foot. What percentage of the class are students who go to school on foot?
小红对本班同学上学的出行情况进行了调查．(1/3)的同学乘汽车上学，(2/5)的同学坐家长的自行车或摩托车上学，其余同学步行上学．步行上学的同学占全班人数的几分之几？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (1/3) - (2/5)</gadget>
<output>4/15 = around 0.266667</output>

<result>4/15 = around 0.266667</result>