A pile of coal weighs (9/10) tons, and (3/5) is transported away, how many tons are left.
一堆煤重(9/10)吨，运走了(3/5)，还有多少吨．
<gadget id="calculator">9 / 10</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(9/10) * (2/5)</gadget>
<output>9/25 = around 0.36</output>

<result>9/25 = around 0.36</result>