A grain and oil store shipped in a batch of rice, sold it on the first day (9/20), and sold 120 kg on the second day. (2/5) of the total amount of rice is left. How many kilograms of this batch of rice are there?
一家粮油店运进一批大米，第一天卖出(9/20)，第二天卖出120千克．还剩下大米总数的(2/5)，这批大米共有多少千克？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">9 / 20</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">1 - (2/5) - (9/20)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">120 / (3/20)</gadget>
<output>800</output>

<result>800</result>