The number A is (1/5) of the number B, and the number A is 20, what is the formula for finding the number B
甲数是乙数的(1/5)，甲数是20，求乙数的算式是多少
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">20 / (1/5)</gadget>
<output>100</output>

<result>100</result>