Cut out the largest semicircle on a piece of paper with a length of 8 cm and a width of 4 cm. What is the area of the remaining paper?
在一张长8厘米，宽4厘米的纸片上，剪出一个最大的半圆，剩下的纸片面积是多少？
<gadget id="calculator">8 * 4</gadget>
<output>32</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">16 / 2</gadget>
<output>8</output>

<gadget id="calculator">3.14 * 8</gadget>
<output>25.12</output>

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

<result>6.88</result>