If the number of boys in a class is 80% of the girls, then the number of boys in the class is ((())/(())).
如果某班男生人数是女生的80%，那么男生人数占全班的((())/(()))．
<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<result>4/9 = around 0.444444</result>