If the length and width of the rectangle are enlarged to 4 times the original size, the area will be enlarged to how many times the original size.
长方形的长和宽都扩大到原来的4倍，面积就扩大到原来的多少倍．
<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<result>16</result>