One wire (1/5) is used for the first time, (1/4) is used for the second time, (1/3) is used for the third time, and this wire is left How much wire.
第一次用去一根铁丝的(1/5)，第二次用去这根铁丝的(1/4)，第三次用去这根铁丝的(1/3)，还剩下这根铁丝的多少．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">(1/5) + (1/4) + (1/3)</gadget>
<output>47/60 = around 0.783333</output>

<gadget id="calculator">1 - (47/60)</gadget>
<output>13/60 = around 0.216667</output>

<result>13/60 = around 0.216667</result>