barrel of oil is sold on the first day (1/3) of the total amount, and another 10 kg is poured in on the second day. Then sell (1/2) of it, and the remaining oil in the barrel is crude oil (4/9). How many kilograms of oil is left in the barrel?
一桶油，第一天卖出总量的(1/3)，第二天又倒入10千克．接着又卖出其中的(1/2)，这时桶里剩油是原油的(4/9)．桶内剩油多少千克？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">10 * (1/2)</gadget>
<output>5</output>

<gadget id="calculator">10 - 5</gadget>
<output>5</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">(1/3) * (1/2)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(4/9) - 1 - (1/6)</gadget>
<output>-13/18 = around -0.722222</output>

<gadget id="calculator">(1/2) + (1/3) + (-13/18)</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">5 / (1/9)</gadget>
<output>45</output>

<result>45</result>