The number of boys in Class 1 is the number of girls (4/5), then the number of girls is the number of the whole class
六1班男生人数是女生人数的(4/5)，那么女生人数是全班人数的多少
<gadget id="calculator">4 + 5</gadget>
<output>9</output>

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

<result>5/9 = around 0.555556</result>