A pile of coal, 5 tons are removed, and there are 7 tons left, how much of this pile of coal is removed
一堆煤，运走了5吨，还剩下7吨，运走的是这堆煤的多少
<gadget id="calculator">5 + 7</gadget>
<output>12</output>

<gadget id="calculator">5 / 12</gadget>
<output>5/12 = around 0.416667</output>

<result>5/12 = around 0.416667</result>