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, and the original number of people in class B is equal to the number of people in class A.
如果把甲班人数的(1/5)调入乙班，则两班人数相等，原来乙班人数是甲班的人数的多少．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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

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