There is half a barrel of oil, the first day sells (2/3) 1 kg less, the second day sells the remaining (2/5) of the first day 1 kg more, and there are 4 kg left in the barrel, ask this barrel of oil How many kilograms are there when filled with oil?
有半桶油，第一天卖出(2/3)少1千克，第二天卖出第一天剩下的(2/5)多1千克，桶里还剩4千克，问这桶油装满油后共有多少千克？
<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">5 / (3/5)</gadget>
<output>25/3 = around 8.333333</output>

<gadget id="calculator">(25/3) - 1</gadget>
<output>22/3 = around 7.333333</output>

<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">(22/3) / (1/3)</gadget>
<output>22</output>

<gadget id="calculator">22 * 2</gadget>
<output>44</output>

<result>44</result>