A rectangle is 10 meters long and 6 meters wide. If the length increases by 2 meters, how many square meters does the area increase?
一个长方形，长是10米，宽是6米．如果长增加2米，面积增加多少平方米．
<gadget id="calculator">2 * 6</gadget>
<output>12</output>

<result>12</result>