A piece of cloth, if its (3/4) is used, there will be 15 meters left; if 60% of it is used, how many meters will be used.
一匹布，用去它的(3/4)，就剩下15米；若用去它的60%，则用去多少米．
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">15 / (1/4)</gadget>
<output>60</output>

<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">60 * (3/5)</gadget>
<output>36</output>

<result>36</result>