pile of coal, use up this pile of coal every day (1/9), how much of this pile of coal is used in 6 days.
一堆煤，每天用去这堆煤的(1/9)，6天一共用去这堆煤的多少．
<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">(1/9) * 6</gadget>
<output>2/3 = around 0.666667</output>

<result>2/3 = around 0.666667</result>