There were 68 refrigerators in the Huai'an shopping mall, but 15 were sold on the first day, and twice as many were sold on the second day. How many refrigerators are there now in the mall?
淮安商场原有68台电冰箱，第一天卖出15台，第二天卖出的是第一天的2倍，现在商场里电冰箱比原来少了多少台？
<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<gadget id="calculator">30 + 15</gadget>
<output>45</output>

<result>45</result>