An old photo with a length of 5 cm and a width of 3 cm, how many square centimeters of photo paper is needed to enlarge the photo to a size of 40 cm?
一张旧照片，长5厘米，宽3厘米，现在要把经放大成长40厘米的大照片，需要多少平方厘米的相纸．
<gadget id="calculator">40 / 5</gadget>
<output>8</output>

<gadget id="calculator">8 ** 2</gadget>
<output>64</output>

<gadget id="calculator">5 * 3 * 64</gadget>
<output>960</output>

<result>960</result>