If the front and back sides of a square plank with a side length of 5 meters are painted, what is the size of the painted area?
边长为5米的正方形木板的正反两面涂油漆，油漆面积的大小是多少．
<gadget id="calculator">5 * 5 * 2</gadget>
<output>50</output>

<result>50</result>