During the festival, a kind of children's educational milk with an original price of x yuan will be priced at 42 yuan after a discount of 8 yuan.
节日期间，一种原价x元的儿童益智牛奶，优惠8元后，售价42元．
<gadget id="calculator">42 + 8</gadget>
<output>50</output>

<result>50</result>