A's number is 16.8, which is 20% less than B's number. What is B's number?
甲数是16.8，比乙数少20%，乙数是多少？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">16.8 / (4/5)</gadget>
<output>21</output>

<result>21</result>