There are 15 tons of yellow sand on the construction site, (2/5) of it was used for the first time, (1/5) for the second time, and ((())/(()) )).
建筑工地上有15吨黄沙，第一次用去了它的(2/5)，第二次用去了(1/5)，两次一共用去了((())/(()))．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(2/5) + (1/5)</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>