Use 36 cm long iron wire to form a rectangle, the ratio of length to width is 5:4, and form a square, what is the difference in area between them in square centimeters?
用36厘米长的铁丝围成一个长方形，长与宽之比是5：4，又围成一个正方形，它们的面积相差多少平方厘米．
<gadget id="calculator">36 / 4</gadget>
<output>9</output>

<gadget id="calculator">9 * 9</gadget>
<output>81</output>

<gadget id="calculator">36 / 2</gadget>
<output>18</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">18 * (5/9)</gadget>
<output>10</output>

<gadget id="calculator">18 - 10</gadget>
<output>8</output>

<gadget id="calculator">10 * 8</gadget>
<output>80</output>

<gadget id="calculator">81 - 80</gadget>
<output>1</output>

<result>1</result>