(9/2)-(7/2)=how much.
(9/2)-(7/2)=多少．
<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">7 / 2</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">(9/2) - (7/2)</gadget>
<output>1</output>

<result>1</result>