The perimeter of a rectangle is 42 decimeters. If the length increases by 3 decimeters and the width decreases by 3 decimeters, the length is twice the width. What is the area of the original rectangle?
长方形的周长42分米，如果长增加3分米，宽减少3分米，长就是宽的2倍，原长方形的面积是多少平米分米？
<gadget id="calculator">42 / 2</gadget>
<output>21</output>

<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">21 * (2/3)</gadget>
<output>14</output>

<gadget id="calculator">14 - 3</gadget>
<output>11</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">21 * (1/3)</gadget>
<output>7</output>

<gadget id="calculator">7 + 3</gadget>
<output>10</output>

<gadget id="calculator">11 * 10</gadget>
<output>110</output>

<result>110</result>