From a rectangular cardboard with a length of 8 cm and a width of 4 cm, after cutting two identical largest circular pieces of paper, what is the area of the remaining paper in square centimeters?
从一张长8厘米，宽4厘米的长方形硬纸片上，剪下两个完全相同的最大圆纸片后，剩下的纸片面积是多少平方厘米？
<gadget id="calculator">8 * 4</gadget>
<output>32</output>

<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<gadget id="calculator">12.56 * 2</gadget>
<output>25.12</output>

<gadget id="calculator">32 - 25.12</gadget>
<output>6.88</output>

<result>6.88</result>