A pile of coal, 40% of it is used, and 2.4 tons are left. If 62.5% of it is used, how many tons are left?
一堆煤，用去它的40%，剩下2.4吨，如果用去它的62.5%，剩下多少吨？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

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

<gadget id="calculator">2.4 / (3/5)</gadget>
<output>4</output>

<gadget id="calculator">62.5 / 100</gadget>
<output>0.625</output>

<gadget id="calculator">1 - 0.625</gadget>
<output>0.375</output>

<gadget id="calculator">4 * 0.375</gadget>
<output>1.5</output>

<result>1.5</result>