yuan per kilogram of oranges, mother bought 8 kilograms, and paid 50 yuan to the salesperson, how much should be recovered.
每千克桔子m元，妈妈买了8千克，付给售货员50元，应找回多少元．
<gadget id="calculator">50 - 8</gadget>
<output>42</output>

<result>42</result>