The playground of Central Primary School used to be 120 meters long and 40 meters wide, but later it was increased by 10 meters in length and 15 meters in width.
中心小学的操场原来长120米，宽40米，后来长增加了10米，宽增加了15米，现在操场的面积比原来增加了多少平方米．
<gadget id="calculator">150 * 55</gadget>
<output>8_250</output>

<gadget id="calculator">120 * 40</gadget>
<output>4_800</output>

<gadget id="calculator">8_250 - 4_800</gadget>
<output>3_450</output>

<result>3_450</result>