There are three piles of chess pieces, the number of chess pieces in each pile is equal, and there are only two colors of black and white. The number of sunspots in the first pile is the same as the number of whites in the second pile; the number of sunspots in the third pile accounts for (3/7) of all sunspots. If the three piles of chess pieces are put together, what fraction of the total number of chess pieces are all white pieces?
有三堆棋子，每堆棋子数都相等，并且都只有黑白两种颜色．第一堆里的黑子数和第二堆里的白子数同样多；第三堆的黑子数占全部黑子的(3/7)．如果把三堆棋子集中到一起，那么所有的白子数占棋子总数的几分之几？
<gadget id="calculator">7 - 3</gadget>
<output>4</output>

<gadget id="calculator">4 - 3</gadget>
<output>1</output>

<gadget id="calculator">1 + 4</gadget>
<output>5</output>

<gadget id="calculator">3 * 4</gadget>
<output>12</output>

<gadget id="calculator">5 / 12</gadget>
<output>5/12 = around 0.416667</output>

<result>5/12 = around 0.416667</result>