A set of "One Hundred Thousand Whys" is 58 yuan, and a set of "Children's Encyclopedia" is 231.20 yuan more expensive than a set of "One Hundred Thousand Whys". Teacher Wang bought a set of "Children's Encyclopedia" and paid the salesperson 300 yuan. How much is the return?
一套《十万个为什么》是58元，一套《少儿百科全书》比一套《十万个为什么》贵231.20元，王老师买一套《少儿百科全书》付给售货员300元，应找回多少元？
<gadget id="calculator">58 + 231.2</gadget>
<output>289.2</output>

<gadget id="calculator">300 - 289.2</gadget>
<output>10.8</output>

<result>10.8</result>