A's number is 16, B's number is 20, how much more B's number than A's number.
甲数是16，乙数是20，乙数比甲数多多少．
<gadget id="calculator">20 - 16</gadget>
<output>4</output>

<gadget id="calculator">4 / 16</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>