One ton of rapeseed can extract (1/5) ton of oil, how many tons of rapeseed are needed to extract 3 tons of rapeseed oil.
每吨菜籽可榨油(1/5)吨，要榨3吨菜油，需要菜籽多少吨．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">3 / (1/5)</gadget>
<output>15</output>

<result>15</result>