There are 48 students in the sixth (first) class, and girls account for the whole class (3/8). After transferring a few girls, the girls account for the whole class (2/5).
六(一)班有48人，女生占全班的(3/8)，转来多少名女生后，女生占全班的(2/5)．
<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">1 - (3/8)</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">48 * (5/8)</gadget>
<output>30</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">30 / (3/5)</gadget>
<output>50</output>

<gadget id="calculator">50 - 48</gadget>
<output>2</output>

<result>2</result>