For a pile of coal, the used weight (1/3) is 2 tons less than the remaining (3/5), and the remaining (2/3) is equal to the used (2/5). How many tons are used?
一堆煤，用掉重量的(1/3)比剩下的(3/5)少2吨，剩下的(2/3)等于用掉的(2/5)．用掉多少吨？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

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

<gadget id="calculator">2 * (2/5)</gadget>
<output>4/5 = around 0.8</output>

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

<gadget id="calculator">(3/5) * (2/5)</gadget>
<output>6/25 = around 0.24</output>

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

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

<gadget id="calculator">(6/25) - (2/9)</gadget>
<output>4/225 = around 0.017778</output>

<gadget id="calculator">(4/5) / (4/225) / (2/5)</gadget>
<output>225/2 = around 112.5</output>

<gadget id="calculator">(2/3) * (225/2)</gadget>
<output>75</output>

<result>75</result>