Xiaoxue has 15.7 yuan, and after giving 2.2 yuan to her sister, she is 0.5 yuan more than her sister. How much is my sister?
小雪有15.7元钱，给妹妹2.2元后，还比妹妹多0.5元．妹妹原来多少钱？
<gadget id="calculator">2.2 + 2.2 + 0.5</gadget>
<output>4.9</output>

<gadget id="calculator">15.7 - 4.9</gadget>
<output>10.8</output>

<result>10.8</result>