A's number is 40, B's number is 30, how much less than A's number
甲数是40，乙数是30，乙数比甲数少多少
<gadget id="calculator">40 - 30</gadget>
<output>10</output>

<gadget id="calculator">10 / 40</gadget>
<output>1/4 = around 0.25</output>

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