multimedia classroom originally had 20 rows of seats, with an average of 35 seats in each row; after expansion, it increased to 38 rows, with 50 seats in each row. How many seats are there after the expansion?
某多媒体教室，原有座位20排，平均每排有35个座位；扩建后增加到38排，每排50个座位，扩建后比原来多多少个座位？
<gadget id="calculator">50 * 38</gadget>
<output>1_900</output>

<gadget id="calculator">35 * 20</gadget>
<output>700</output>

<gadget id="calculator">1_900 - 700</gadget>
<output>1_200</output>

<result>1_200</result>