Naughty spent 47.5 yuan to buy a schoolbag and 12.7 yuan to buy a pencil case. He paid the salesperson 100 yuan. How much should he get back?
淘气买书包用了47.5元，买铅笔盒用了12.7元，他付给售货员100元，应找回多少元？
<gadget id="calculator">47.5 + 12.7</gadget>
<output>60.2</output>

<gadget id="calculator">100 - 60.2</gadget>
<output>39.8</output>

<result>39.8</result>