The number of boys in class 1 of a certain school used to be girls (5/6), but later 2 boys and 2 girls were transferred away, and now the number of boys was girls (9/11). How many boys were there in Class 1?
某校六1班原来男生人数是女生的(5/6)，后来转走2名男生和2名女生，这时男生人数是女生的(9/11)．六1班原来有男生多少人．
<gadget id="calculator">9 / 11</gadget>
<output>9/11 = around 0.818182</output>

<gadget id="calculator">2 * (9/11)</gadget>
<output>18/11 = around 1.636364</output>

<gadget id="calculator">2 - (18/11)</gadget>
<output>4/11 = around 0.363636</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(5/6) - (9/11)</gadget>
<output>1/66 = around 0.015152</output>

<gadget id="calculator">(4/11) / (1/66)</gadget>
<output>24</output>

<gadget id="calculator">24 * (5/6)</gadget>
<output>20</output>

<result>20</result>