The number A is 20 less than 80% of the number B. Given that the number A is 40, what is the number B?
甲数比乙数的80%还少20，已知甲数是40，乙数是多少？
<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">60 * (5/4)</gadget>
<output>75</output>

<result>75</result>