1 yuan per person is required to take the bus. If you use the card, you will be charged 0.5 yuan each time. How much cheaper is it to use the card than to insert the coin?
乘坐公交车每人需投币1元，如果刷卡，则每次扣费0.5元，刷卡比投币便宜多少
<gadget id="calculator">1 - 0.5</gadget>
<output>0.5</output>

<gadget id="calculator">0.5 / 1</gadget>
<output>0.5</output>

<result>0.5</result>