□/24*4+(24*□-□*15)/6-16=4, how much is □=.
□/24*4+(24*□-□*15)/6-16=4，求□=多少．
<gadget id="calculator">16 + 4</gadget>
<output>20</output>

<gadget id="calculator">1 / 24</gadget>
<output>1/24 = around 0.041667</output>

<gadget id="calculator">(1/24) * 4</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">24 * (1/6)</gadget>
<output>4</output>

<gadget id="calculator">15 / 6</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">4 - (5/2)</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(1/6) + (3/2)</gadget>
<output>5/3 = around 1.666667</output>

<gadget id="calculator">20 / (5/3)</gadget>
<output>12</output>

<result>12</result>