4 small squares with a side length of 5 cm are put together to form a large square. What is the perimeter of the large square?
4个边长是5厘米的小正方形拼成一个大正方形，拼成的大正方形的周长是多少．
<gadget id="calculator">5 + 5</gadget>
<output>10</output>

<gadget id="calculator">10 * 4</gadget>
<output>40</output>

<result>40</result>