Xiaoxiao spent 6.8 yuan to buy books, 6.3 yuan to buy pens, and 15 yuan to the salesperson. How much should I get back?
笑笑买书用去6.8元，买钢笔用去6.3元，付给售货员15元，应找回多少元？
<gadget id="calculator">15 - 6.8 - 6.3</gadget>
<output>1.9</output>

<result>1.9</result>