How many small squares with a side length of 1 cm are needed to assemble a large square with a side length of 4 cm.
拼一个边长4cm的大正方形，至少需要多少个边长1cm的小正方形．
<gadget id="calculator">4 * 4</gadget>
<output>16</output>

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

<gadget id="calculator">16 / 1</gadget>
<output>16</output>

<result>16</result>