A barrel of oil is used up twice, the first time (2/3) is used, and the second time (2/3) kilograms, how many kilograms are there in this barrel of oil?
一桶油分两次用完，第一次用去(2/3)，第二次用去(2/3)千克，这桶油共有多少千克．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 - (2/3)</gadget>
<output>1/3 = around 0.333333</output>

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

<result>2</result>