After 100 meters of plastic is used up (3/10), how many meters are left?
100米塑料而用去它的(3/10)后，还剩多少米．
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (3/10)</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">100 * (7/10)</gadget>
<output>70</output>

<result>70</result>