(((15/28)-(11/36))*(21/29)+□/(16/21))/16(1/2)=(5/9), then□=how much.
(((15/28)-(11/36))*(21/29)+□/(16/21))/16(1/2)=(5/9)，则□=多少．
<gadget id="calculator">11 / 36</gadget>
<output>11/36 = around 0.305556</output>

<gadget id="calculator">21 / 29</gadget>
<output>21/29 = around 0.724138</output>

<gadget id="calculator">2 / 33</gadget>
<output>2/33 = around 0.060606</output>

<gadget id="calculator">(11/36) * (21/29) * (2/33)</gadget>
<output>7/522 = around 0.01341</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">15 / 28</gadget>
<output>15/28 = around 0.535714</output>

<gadget id="calculator">(15/28) * (21/29) * (2/33)</gadget>
<output>15/638 = around 0.023511</output>

<gadget id="calculator">(5/9) - (15/638)</gadget>
<output>3_055/5_742 = around 0.532045</output>

<gadget id="calculator">(7/522) + (3_055/5_742)</gadget>
<output>6/11 = around 0.545455</output>

<gadget id="calculator">21 / 16</gadget>
<output>21/16 = around 1.3125</output>

<gadget id="calculator">(21/16) * (2/33)</gadget>
<output>7/88 = around 0.079545</output>

<gadget id="calculator">(6/11) / (7/88)</gadget>
<output>48/7 = around 6.857143</output>

<result>48/7 = around 6.857143</result>