A pot of oil, pour out (1/4) for the first time, then add 60 grams, pour out (3/5) of the oil in the pot for the second time, pour out 120 grams for the third time, and there are 120 grams left in the pot, How much oil is there in the pot?
一壶油，第一次倒出(1/4)，然后加入60克，第二次倒出壶中油的(3/5)，第三次倒出120克，壶中还剩下120克，原来壶中有多少油？
<gadget id="calculator">120 + 120</gadget>
<output>240</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">240 / (2/5)</gadget>
<output>600</output>

<gadget id="calculator">600 - 60</gadget>
<output>540</output>

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

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">540 / (3/4)</gadget>
<output>720</output>

<result>720</result>