Aunt Zhang bought two books in the bookstore, one for 10.6 yuan and the other for 25.8 yuan. Aunt Zhang paid 50 yuan. How much should I get back?
张阿姨在书店买了两本书，一本10.6元，另一本25.8元，张阿姨付了50元，应找回多少元？
<gadget id="calculator">10.6 + 25.8</gadget>
<output>36.4</output>

<gadget id="calculator">50 - 36.4</gadget>
<output>13.6</output>

<result>13.6</result>