A rectangular playground is 70 meters long and 30 meters wide. After the expansion, the length and width are both increased by 10 meters. How many meters has the perimeter of the playground increased?
一个长方形的操场，长是70米，宽是30米．扩建后长和宽都增加10米，这个操场的周长增加了多少米．
<gadget id="calculator">70 + 10 + 30 + 10</gadget>
<output>120</output>

<gadget id="calculator">120 * 2</gadget>
<output>240</output>

<gadget id="calculator">70 + 30</gadget>
<output>100</output>

<gadget id="calculator">100 * 2</gadget>
<output>200</output>

<gadget id="calculator">240 - 200</gadget>
<output>40</output>

<result>40</result>