used to have 13.8 yuan, but yesterday I bought a 6.8 yuan storybook, and today my father gave me another 2.5 yuan, how much money do I have now?
我原来有13.8元钱，昨天买了一本6.8元的故事书，今天爸爸又给了我2.5元，现在我还有多少钱？
<gadget id="calculator">13.8 - 6.8</gadget>
<output>7</output>

<gadget id="calculator">7 + 2.5</gadget>
<output>9.5</output>

<result>9.5</result>