There are three piles of chess pieces, each of which has the same number of pieces, and there are only two types of black and white pieces. The number of black pieces in the first pile is the same as the number of white pieces in the second pile, and the number of black pieces in the third pile accounts for all black pieces (2 /5), put the three piles of chess pieces together, and ask what percentage of the whole chess pieces are white pieces?
有三堆棋子，每堆棋子数一样多，并且都只有黑白两种，第一堆里的黑子数与第二堆里的白子数一样多，第三堆里的黑子占全部黑子的(2/5)，把三堆棋子集中在一起，问白子占全部棋子的几分之几？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</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">(1/3) / (3/5)</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">1 - (5/9)</gadget>
<output>4/9 = around 0.444444</output>

<result>4/9 = around 0.444444</result>