The diameter of a circular island is 50m, the middle is a circular flower bed with a diameter of 10m, and the other places are lawns. If the cost of planting turf per square meter is 3.50 yuan, how much will it cost to make the lawn well?
一个圆形环岛的直径是50m，中间是一个直径为10m的圆形花坛，其他地方是草坪．如果每平方米的种植草皮的费用是3.50元，求做好这个草坪的费用是多少？
<gadget id="calculator">50 / 2</gadget>
<output>25</output>

<gadget id="calculator">25 ** 2</gadget>
<output>625</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">625 - 25</gadget>
<output>600</output>

<gadget id="calculator">3.14 * 600</gadget>
<output>1_884</output>

<gadget id="calculator">3.5 * 1_884</gadget>
<output>6_594</output>

<result>6_594</result>