In order to green the campus, a batch of saplings should be planted, and the survival rate of these saplings is 80% to 90%. If it is required to ensure that 720 saplings survive, at least how many saplings need to be planted.
为绿化校园，要栽种一批树苗，这批树苗的成活率是80%～90%．如果要求保证有720棵树苗成活，至少需要栽种多少棵．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">720 / (4/5)</gadget>
<output>900</output>

<result>900</result>