There is a batch of cement on the construction site, 20% of the total amount is used on the first day, and 25% of the total amount is used on the second day, leaving 300 kg. How many kg of this batch of cement are there in total?
工地里有一批水泥，第一天用去总数的20%，第二天用去总数的25%，还剩下300千克，这批水泥一共有多少千克？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/5) - (1/4)</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">300 / (11/20)</gadget>
<output>6_000/11 = around 545.454545</output>

<result>6_000/11 = around 545.454545</result>