Qiqi bought a copy of "Grimm's Fairy Tales" for 8.3 yuan; and another copy of "Little Boy" for 9.5 yuan. She paid her aunt 20 yuan, how much should she get back?
琦琦买了一本《格林童话》，花了8.3元；又买了一本《小小少年》，花了9.5元．她付给阿姨20元，应该找回多少钱？
<gadget id="calculator">8.3 + 9.5</gadget>
<output>17.8</output>

<gadget id="calculator">20 - 17.8</gadget>
<output>2.2</output>

<result>2.2</result>