The chicken farm was originally 60 meters long and 50 meters wide. Now it is planned to shorten the length of the chicken farm by 20 meters and the width by 10 meters. How many square meters has the chicken farm been reduced?
养鸡场原来长60米，宽50米．现准备将养鸡场的长缩短20米，宽缩短10米，养鸡场缩小了多少平方米？
<gadget id="calculator">60 * 50</gadget>
<output>3_000</output>

<gadget id="calculator">60 - 20</gadget>
<output>40</output>

<gadget id="calculator">50 - 10</gadget>
<output>40</output>

<gadget id="calculator">40 * 40</gadget>
<output>1_600</output>

<gadget id="calculator">3_000 - 1_600</gadget>
<output>1_400</output>

<result>1_400</result>