A pile of chess pieces has two colors of black and white, among which black pieces account for (7/22), if 10 white pieces are added, then black pieces account for (2/7). So, how many pieces are there in this pile.
一堆棋子有黑白两种颜色，其中黑子占(7/22)，若增加10枚白子，这时黑子占(2/7)．那么，这堆棋子有多少枚．
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">10 * (2/7)</gadget>
<output>20/7 = around 2.857143</output>

<gadget id="calculator">7 / 22</gadget>
<output>7/22 = around 0.318182</output>

<gadget id="calculator">(7/22) - (2/7)</gadget>
<output>5/154 = around 0.032468</output>

<gadget id="calculator">(20/7) / (5/154)</gadget>
<output>88</output>

<result>88</result>