The school cafeteria brings (2/5) tons of coal, uses (1/4) on the first day, and uses the remaining half on the second day, how many tons are left?
学校食堂运来(2/5)吨煤，第一天用去(1/4)，第二天用去剩下的一半，还剩下多少吨？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(2/5) * (3/4) * (1/2)</gadget>
<output>3/20 = around 0.15</output>

<result>3/20 = around 0.15</result>