There are 120 cars, 30% are sold, how many cars are left?
有120辆汽车，售出30%，还剩多少辆．
<gadget id="calculator">30 / 100</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">120 * (7/10)</gadget>
<output>84</output>

<result>84</result>