If 270 saplings with a survival rate of 90% survived, how many saplings were planted in total?
成活率是90%的树苗，活了270棵，那么一共栽了多少棵．
<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">270 / (9/10)</gadget>
<output>300</output>

<result>300</result>