A batch of chemical fertilizers is 20 tons in total, sold (3/4), how many tons are left? how many tons
一批化肥共20吨，卖了(3/4)，剩下多少吨？多少吨
<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">20 * (1/4)</gadget>
<output>5</output>

<result>5</result>