If 1/5 of the number of people in class A is transferred to class B, the number of people in the two classes will be equal. The original number of people in class A is the same as that in class B.
把甲班人数的(1/5)调入乙班，则两班人数相等，原来甲班人数是乙班的多少．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">50 * (1/5)</gadget>
<output>10</output>

<gadget id="calculator">50 - 10</gadget>
<output>40</output>

<gadget id="calculator">40 - 10</gadget>
<output>30</output>

<gadget id="calculator">50 / 30</gadget>
<output>5/3 = around 1.666667</output>

<result>5/3 = around 1.666667</result>