The price of a pen is 9.8 yuan, Xiao Ming has 6 yuan, how much is the difference to buy this pen
一支钢笔的价格是9.8元，小明有6元，要买这支钢笔，还差多少
<gadget id="calculator">9.8 - 6</gadget>
<output>3.8</output>

<result>3.8</result>