There is a square nursery, one side is against the wall, and the other three sides are surrounded by bamboo fences. The total length of the bamboo fence is 81 decimeters. If one holly is planted every 9 square decimeters in the nursery, how many hollies can be planted in this nursery?
有一个正方形苗圃，一面靠墙，其它三面围竹篱笆，竹篱笆的总长是81分米，如果苗圃内每9平方分米栽一棵冬青，则这块苗圃能中多少棵冬青？
<gadget id="calculator">81 / 3</gadget>
<output>27</output>

<gadget id="calculator">27 / 9</gadget>
<output>3</output>

<gadget id="calculator">27 * 3</gadget>
<output>81</output>

<result>81</result>