The landscaping team wanted to plant a batch of saplings. On the first day, 210 were planted, and the remaining 20% were planted on the second day. After two days, the total number (2/5) was still unfinished. How many saplings are there in total?
园林绿化队要栽一批树苗，第一天栽了210棵，第二天栽了剩下的20%，两天后还有总数的(2/5)没有完成，这批树苗一共多少棵？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(2/5) / (4/5)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">210 / (1/2)</gadget>
<output>420</output>

<result>420</result>