Xiao Ming's mother takes 500 yuan to go to the supermarket to buy 3 boxes of yogurt and 1 box of pure milk. How much money is left? Known premium yogurt 35 yuan / box, pure milk 50 yuan / box.
小明的妈妈拿500元钱，去超市买3箱酸酸乳和1箱纯牛奶，还剩多少元？已知优酸乳35元/箱，纯牛奶50元/箱．
<gadget id="calculator">35 * 3</gadget>
<output>105</output>

<gadget id="calculator">105 + 50</gadget>
<output>155</output>

<gadget id="calculator">500 - 155</gadget>
<output>345</output>

<result>345</result>