For a barrel of oil, the whole barrel of oil (1/3) is used for the first time, and the remaining oil (1/3) is used for the second time, leaving 180kg of oil. How many kilograms of this barrel of oil are there?
一桶油，第一次用去整桶油的(1/3)，第二次用去了余下油的(1/3)，还剩180kg油，这桶油原来有多少千克？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(2/3) * (1/3)</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">1 - (1/3) - (2/9)</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">180 / (4/9)</gadget>
<output>405</output>

<result>405</result>