For a pile of coal, (1/3) of it is removed for the first time, and (1/4) of it is removed for the second time, how much of this pile of coal is removed in total.
一堆煤，第一次运走它的(1/3)，第二次运走它的(1/4)，两次一共运走这堆煤的多少．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

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

<gadget id="calculator">(1/3) + (1/4)</gadget>
<output>7/12 = around 0.583333</output>

<result>7/12 = around 0.583333</result>