A pile of sand is used every day (2/5), how much is used in 2 days.
一堆沙子，每天用去(2/5)，2天用去多少．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/5) * 2</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>