Given that the perimeter of a rectangle is 24m, if its length and width are increased by 3m, how much will its area increase in m**2.
已知一个长方形的周长是24m，如果它的长和宽各增加3m，那么它的面积将会增加多少m**2．
<gadget id="calculator">24 / 2</gadget>
<output>12</output>

<gadget id="calculator">3 * 12</gadget>
<output>36</output>

<gadget id="calculator">36 + 9</gadget>
<output>45</output>

<result>45</result>