If the number of boys accounts for 2/3 of the number of girls, then the number of girls is the number of the whole class
男生人数占女生人数的(2/3)，那么女生人数是全班人数的多少
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

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

<gadget id="calculator">1 / (5/3)</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>