There is a pile of sand, the first truck carries away (1/8) of the pile of sand, the second truck carries more (2/8) of the pile of sand than the first truck, and the rest is carried by the third truck Come on, what fraction of this pile of sand does the third truck take away?
有一堆沙子，第一辆卡车运走这堆沙子的(1/8)，第二辆卡车比第一辆多运这堆沙子的(2/8)，剩下的由第三辆卡车全部运走，第三辆卡车运走这堆沙子的几分之几？
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">2 / 8</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/8) + (1/4)</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">1 - (1/8) - (3/8)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>