A's number is 60, which is 20 more than B's (2/5), what is B's number?
甲数是60，比乙数的(2/5)多20，乙数是多少．
<gadget id="calculator">60 - 20</gadget>
<output>40</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">40 / (2/5)</gadget>
<output>100</output>

<result>100</result>