There are 375 seats downstairs in the movie theater, and 135 seats are less upstairs than downstairs. How many seats are there in total in the movie theater?
电影院楼下有375个座位，楼上比楼下少135个座位，电影院一共有多少个座位？
<gadget id="calculator">375 - 135</gadget>
<output>240</output>

<gadget id="calculator">240 + 375</gadget>
<output>615</output>

<result>615</result>