Teacher Wang bought a storybook at Xinhua Bookstore for 18 yuan and a teaching book for 22 yuan. He gave the salesperson 50 yuan. How much should the salesperson give Teacher Wang?
王老师在新华书店买了一本故事书18元，一本教学用书22元，他给营业员50元，营业员应找给王老师多少钱？
<gadget id="calculator">50 - 18 - 22</gadget>
<output>10</output>

<result>10</result>