A rectangular piece of land is 300 meters long, and its width is less than its length (3/10). How many hectares does this piece of land occupy?
一块长方形地，长300米，宽比长少(3/10)，这块地占多少公顷？
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">300 * (3/10)</gadget>
<output>90</output>

<gadget id="calculator">300 - 90</gadget>
<output>210</output>

<gadget id="calculator">210 / 10_000</gadget>
<output>21/1_000 = around 0.021</output>

<gadget id="calculator">300 * (21/1_000)</gadget>
<output>63/10 = around 6.3</output>

<result>63/10 = around 6.3</result>