There are 548 boxes of fruit in the fruit shop, 234 boxes are sold on the first day, and 175 boxes are sold on the second day. How many boxes are left unsold? (answer in two ways)
水果店有548箱水果，第一天卖出234箱，第二天卖出175箱，还剩下多少水果没有卖出？(用两种方法解答)
<gadget id="calculator">234 + 175</gadget>
<output>409</output>

<gadget id="calculator">548 - 409</gadget>
<output>139</output>

<result>139</result>