If the radius of a circle is increased by 20%, the area of the circle will be increased by how much.
把一个圆的半径增加20%，则圆的面积比原来增加多少．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">5 * (6/5)</gadget>
<output>6</output>

<gadget id="calculator">6 ** 2</gadget>
<output>36</output>

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

<gadget id="calculator">36 - 25</gadget>
<output>11</output>

<gadget id="calculator">3.14 * 11</gadget>
<output>34.54</output>

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<gadget id="calculator">34.54 / 78.5</gadget>
<output>0.44</output>

<result>0.44</result>