If you cultivate a piece of land, on the first day you plow 5 hectares less than half of the whole land, on the second day you plow 2 hectares more than half of the whole land, and on the third day after you plow 20 hectares, there are still 5 hectares left. How many hectares is the land?
耕一块地，第一天耕的比整块地的一半少5公顷，第二天耕的比整块地的一半多2公顷，第三天耕了20公顷后还剩下5公顷，这块地有多少公顷？
<gadget id="calculator">38 - 20</gadget>
<output>18</output>

<gadget id="calculator">18 + 2</gadget>
<output>20</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">20 / (1/2)</gadget>
<output>40</output>

<gadget id="calculator">40 - 5</gadget>
<output>35</output>

<gadget id="calculator">35 / (1/2)</gadget>
<output>70</output>

<result>70</result>