Jiahe Supermarket held a big discount event during the National Day. Anyone who purchased more than 200 yuan of goods can get 50 yuan in cash. Mom has 520 yuan. How much do you think she can buy at most?
家和超市在国庆期间举行优惠大酬宾活动，凡购满200元商品的可回赠现金50元，妈妈有520元钱，你认为她最多能买到多少元的商品．
<gadget id="calculator">50 * 2</gadget>
<output>100</output>

<gadget id="calculator">520 + 100 + 50</gadget>
<output>670</output>

<result>670</result>