Xiaonan, Xiaobei and Xiaodong participated in the relay race. Xiaonan ran the first baton. After finishing (1/3), he passed the baton to Xiaobei. Pass it to Xiaodong, Xiaodong ran to the finish line, what fraction of the whole journey did Xiaodong run?
小南、小北和小东参加接力赛，小南跑第一棒，跑完全程的(1/3)后，把接力棒传给小北，小北接着跑完全程的(2/5)，把接力棒传给小东，小东跑到了终点，小东跑了全程的几分之几？
<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>