There are three piles of Go pieces, each with the same number of pieces. Among them, the white pieces account for (4/9) of all the pieces, the number of black pieces in the first pile is the same as that in the second pile, and how much the third pile of black pieces accounts for all the black pieces.
有三堆围棋子，每堆棋子总数一样多．其中白子占全部棋子的(4/9)，第一堆里的黑子和第二堆里的白子同样多，第三堆黑子占全部黑子的多少．
<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">1 - (4/9)</gadget>
<output>5/9 = around 0.555556</output>

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

<gadget id="calculator">(5/9) - (1/3)</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">(2/9) / (5/9)</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>