How many tons are (3/8) tons of coal after (1/4) is used up?
(3/8)吨煤用去(1/4)后是多少吨．
<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</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">(3/8) * (3/4)</gadget>
<output>9/32 = around 0.28125</output>

<result>9/32 = around 0.28125</result>