The number B is 15, which is 5 less than the number A, and how much less the number B is than the number A.
乙数是15，比甲数少5，乙数比甲数少多少．
<gadget id="calculator">15 + 5</gadget>
<output>20</output>

<gadget id="calculator">5 / 20</gadget>
<output>1/4 = around 0.25</output>

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