A's number is 4.5, which is 0.5 more than B's (1/2), what is B's number?
甲数是4.5，比乙数的(1/2)多0.5，乙数是多少？
<gadget id="calculator">4.5 - 0.5</gadget>
<output>4</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">4 / (1/2)</gadget>
<output>8</output>

<result>8</result>