Zhou Mingming bought a copy of "Xinhua Dictionary" with a price of 19.90 yuan and a copy of "One Hundred Thousand Whys" with a price of 24.35 yuan with a piece of 50 yuan. How much should the salesperson give him?
周明明用一张50元的人民币，买了一本价格是19.90元的《新华字典》和一本价格是24.35元的《十万个为什么》，售货员应该找给他多少元．
<gadget id="calculator">19.9 + 24.35</gadget>
<output>44.25</output>

<gadget id="calculator">50 - 44.25</gadget>
<output>5.75</output>

<result>5.75</result>