A circular aquarium has a radius of 10 meters, and there is a circular island in the middle with a diameter of 8 meters. What is the water surface area of this aquarium in square meters?
一个圆形养鱼池，半径是10米，中间有一个圆形小岛，直径是8米，这个养鱼池的水面面积是多少平方米？
<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

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

<gadget id="calculator">3.14 * 16</gadget>
<output>50.24</output>

<gadget id="calculator">314 - 50.24</gadget>
<output>263.76</output>

<result>263.76</result>