A pile of coal weighs (1/2) ton, the first time (1/5) is removed, and the second time (1/6) is removed, what fraction of the total is left?
一堆煤重(1/2)吨，第一次运走(1/5)，第二次运走(1/6)，还剩下总数的几分之几？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 - (1/5) - (1/6)</gadget>
<output>19/30 = around 0.633333</output>

<result>19/30 = around 0.633333</result>