There are (5/4) tons of rice in the cafeteria, if (1/5) of it is used, how many tons are left?
食堂有大米(5/4)吨，用去它的(1/5)，还剩多少吨？
<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

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

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(5/4) * (4/5)</gadget>
<output>1</output>

<result>1</result>