Use 9 small squares with a side length of 1 decimeter to form a large square. What is the area of this large square?
用9个边长为1分米的小正方形，围成一个大正方形，这个大正方形的面积是多少．
<gadget id="calculator">1 * 1 * 9</gadget>
<output>9</output>

<result>9</result>