A's number (2/3) is 8, B's number is 20 (4/5), what is the difference between A and B's two numbers?
甲数的(2/3)是8，乙数是20的(4/5)，甲、乙两数的差是多少．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">20 * (4/5)</gadget>
<output>16</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">8 / (2/3)</gadget>
<output>12</output>

<gadget id="calculator">16 - 12</gadget>
<output>4</output>

<result>4</result>