copy of "Fairy Tale" is priced at 5.2 yuan, a copy of "The Brain King" is priced at 13.8 yuan, Li Ming has 20 yuan, he buys each, how much money is left?
一本《童话故事》定价5.2元，一本《动脑筋大王》定价13.8元，李明有20元，他各买一本，还剩多少元？
<gadget id="calculator">5.2 + 13.8</gadget>
<output>19</output>

<gadget id="calculator">20 - 19</gadget>
<output>1</output>

<result>1</result>