In a square field, a tree is planted at an interval of 8 meters along the perimeter, and a total of 100 trees are planted. It is known that the corn harvested in this field is 28 tons. How many tons of corn can be harvested per hectare on average in this field?
一块正方形地，沿四周每隔8米种一棵树，一共种了100棵，已知这块地里种的玉米共收28吨，这块地平均每公顷收玉米多少吨？
<gadget id="calculator">100 / 4</gadget>
<output>25</output>

<gadget id="calculator">100 / 4 / 10_000</gadget>
<output>1/400 = around 0.0025</output>

<gadget id="calculator">8 * 25 * 8 * (1/400)</gadget>
<output>4</output>

<gadget id="calculator">28 / 4</gadget>
<output>7</output>

<result>7</result>