The survival rate of saplings is 98%. To ensure the survival of 490 saplings, at least how many saplings must be planted.
树苗的成活率是98%，要保证成活490棵树苗，至少要栽多少棵树苗．
<gadget id="calculator">98 / 100</gadget>
<output>49/50 = around 0.98</output>

<gadget id="calculator">490 / (49/50)</gadget>
<output>500</output>

<result>500</result>