A wire, its (1/3) was used for the first time, and its (1/5) was used for the second time, what fraction of the wire is left?
一根电线，第一次用去了它的(1/3)，第二次用去了它的(1/5)，还剩这根电线的几分之几？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

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

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

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