How many small squares with a side length of 1 cm are needed to assemble a large square with a side length of 3 cm. (There is no gap between the small squares, and there is no overlap)
拼一个边长3厘米的大正方形，至少需要多少个边长1厘米的小正方形．(小正方之间既无空隙，有不重叠)
<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">1 * 1</gadget>
<output>1</output>

<gadget id="calculator">9 / 1</gadget>
<output>9</output>

<result>9</result>