The sum of the numbers A and B is 100, the number B is 20, and the number B is the number A.
甲、乙两数的和是100，乙数是20，乙数是甲数的多少．
<gadget id="calculator">100 - 20</gadget>
<output>80</output>

<gadget id="calculator">20 / 80</gadget>
<output>1/4 = around 0.25</output>

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