A rectangular orchard 100 meters long and 65 meters wide. If the length and width are doubled, how many hectares will the area of the orchard increase?
一个长100米，宽65米的长方形果园．如果长与宽都扩大1倍，那么果园的面积增加多少公顷？
<gadget id="calculator">100 * 65</gadget>
<output>6_500</output>

<gadget id="calculator">6_500 / 10_000</gadget>
<output>13/20 = around 0.65</output>

<result>13/20 = around 0.65</result>