A wire is 15 meters long, (2/5) is used for the first time, and (1/3) is used for the second time, how many meters are left?
一根铁丝长15米，第一次用去(2/5)，第二次用去(1/3)，这时还剩多少米？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

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

<gadget id="calculator">15 * (4/15)</gadget>
<output>4</output>

<result>4</result>