For y yuan per kilogram of pork, Xiaolan buys 3 kilograms of pork and pays 100 yuan, how much should she get back.
每千克猪肉y元，小兰买3千克猪肉，付100元钱，应找回多少．
<gadget id="calculator">100 - 3</gadget>
<output>97</output>

<result>97</result>