Lili spent 7.6 yuan to buy a pen, and 5.1 yuan less to buy an exercise book than to buy a pen. She paid the salesperson 20.00 yuan, how much should she get back?
丽丽买钢笔用去7.6元，买练习本比买钢笔少用5.1元，付给售货员20.00元钱，应找回多少元？
<gadget id="calculator">7.6 - 5.1</gadget>
<output>2.5</output>

<gadget id="calculator">2.5 + 7.6</gadget>
<output>10.1</output>

<gadget id="calculator">20 - 10.1</gadget>
<output>9.9</output>

<result>9.9</result>