If (1/5) of the number B is the number A, then the incorrect one of the following three options is how much less the number A is than the number B
如果乙数的(1/5)是甲数，那么下面三个选项中不正确的是甲数比乙数少多少
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>